So you told your boss that you bought your Android smartphone so that you could track your business calls, be more effective when travelling for your company, have easy access to Gmail and keep your organisation's Twitter feed current. But we know what's really going on - you got that smartphone because it was cool and because you wanted to play with all the apps. (And possibly because it wasn't Apple or AT&T.)

Just for the heck of it, I've gathered eight free apps that are just plain fun to use. A couple of them are also actually useful; another two are sort of useful (if you stretch the point a bit); the last four are just there to play with.

And if you have any to add, please mention them in the article comments.

Actually useful apps

Carrr Matey

Lionebra Studios

Avast, me hearties! Car owners who live in cities often have to park on the street. Less urban folks who go to the mall get to park in huge lots the size of a small country. Either way, it's easy to forget where you left your car. This is what makes a parking reminder app such as Carrr Matey so useful.

Carrr Matey

There are a number of similar apps out there - including the increasingly popular Car Locator - but as far as I'm concerned, this is the best one out there. Not only does it let you mark where you've parked your car and then help you find it again (using the phone's GPS), but Carrr Matey has at least one thing the others do not.

It talks like a pirate.

So you don't park your car - you drop anchor. Can't remember where your car, uh, ship is? Click on the Find Vessel button. Don't want the Navy - ie, the police - to give you a ticket when the meter runs out? Set the timer. And if you want to make note of which part of the garage your vessel is in, click on the Harbor button and you can note (by drawing on your touch screen) the level, letter or space you're using -- on a treasure map.

So if you wish that Talk Like a Pirate Day lasted all year long, Carrr Matey is the app to try.

Tricorder

Moonblink

TricorderNow that the latest Star Trek movie has revamped the entire franchise, it's become more acceptable to admit that you're a Star Trek geek. So you don't have to hide the fact that you've downloaded an app onto your Android phone called Tricorder. And that it beeps just like a "real" tricorder. And looks like something Scotty would use to check the engines.

But strangely enough, Tricorder also does practical stuff. It performs an acoustical analysis of the ambient sound in your area (useful if you're about to record a podcast). It measures the strength of the cellular and Wi-Fi signals in your area. It locates the closest GPS signal and tells you what satellites are in range -- not bad to have if you want to figure out what's going on with your GPS service. It monitors the local gravitational and magnetic fields (yes, really!). Oh, and it tracks solar flares -- just in case you're worried about them.

In other words, if you're a tech nerd, Tricorder actually offers up some interesting data. And it does all this with one of the coolest interface designs this side of the Neutral Zone.

Somewhat useful apps

Bic Concert Lighter

Bic USA Inc.

So here you are at a concert of your favorite band, and you're just having a great time, jumping up and down and screaming the lyrics. Now it's time to really show your appreciation by flicking on your lighter - but the management of the concert hall has decreed that a couple of thousand lighters being waved by a bunch of enthusiastic music fans constitute a fire hazard.

What do you do?

Bic Concert Lighter

You pull out your phone and open up your Bic Concert Lighter app.

What you get is a full-screen image of a Bic lighter - you can choose from several designs, including Astrology, Flick my BIC, Geometr

ics and Tattoos. You then "flick" the lighter by touching the screen (with appropriate sound effect) and you get a flame. D

ip your smartphone down to the left or right, and the flame moves (as a real one would) to stay upright.

The Bic Concert Lighter is available for the iPhone, iPod and BlackBerry Storm as well. Bic includes with its app a warning that children shouldn't play with lighters -- even virtual ones. The warning adds that this application "should only be used by adults 19 years of age or older."

Because they m

ay try to light a virtual cigarette with it?

Easy Metal Detector Lite

Androidika

Easy Metal DetectorNeed a way to pay for your new Android smartphone? No problem - just search for all those coins that people have dropped around your neighborhood, with Easy Metal Detector Lite.

How does it work? Well, apparently your phone uses a magnetometer for its compass function -- and magnets are good at finding metal.

There are actually a few worthwhile metal-detecting apps out there, such as Metal Detector. Metal Detector works just fine, but Easy Metal Detector Lite has a snazzier interface and uses a friendly beeping sound to let you know that you've struck pay dirt. (Easy Metal Detector Lite also has a version without ads, called Easy Metal Detector, for 99 cents.)

There isn't an extremely powerful magnet in your phone, and as a result, you have to be pretty near the metal to register it significantly. So if you want to know the truth, you're not going to find an awful lot of coins with this app. But that's beside the point -- it's just plain fun.

Just-for-fun apps

My Magic 8 Ball

CWE Software

Magic 8 BallIf you want to figure out what's going to happen in your future, you can browse through Google News, call your banker, read the stars - or you can install the My Magic 8 Ball app on your Android smartphone.

What do you get with it? An image of the Magic 8 Ball that, when you shake your phone, offers up one of 20 answers to your questions, such as "My reply is no," "Yes, definitely" and "Better not tell you now." If your phone doesn't react to a firm shake (mine did), there is a button you can press for your Magic 8 Ball answer.

There are actually several Magic 8 Ball apps available for Android phones -- I chose this one because it was free and simple and used the same 20 answers you got from the original Magic 8 Ball toy. And because when I asked it, "Should I review this app?" it answered with a firm, "Yes."

Spark

Diotasoft

Hey, kids! Want to surprise and astound your friends?

Rev up Spark, an Android app from French company Diotasoft, and then ask your friends to touch the screen. There will be a lightning effect (in any color you want) and the phone will vibrate, giving the impression (well, sort of the impression) that they've just receive a real electric shock! Hours - well, minutes - of laughs!

But wait - there's more!

Well, no - actually, that's it. But it is sort of fun to run your finger across the screen and watch the colored lightning flare out.

Pinball

Magma Mobile

PinballNon-video games may have gone out of style, but some of us still remember pinball as the ultimate test of dexterity, endurance and skill. If you were a pinball wizard - -or just enjoyed the game - you may want to try Pinball.

The app offers six different themes; you touch the screen to release the ball and control the flippers. As the ball bounces around the game area, you get satisfying sound effects, and when you're done, it keeps track of your score totals.

You can also reconfigure which buttons or keyboard keys control the flippers - for example, since I wasn't satisfied to simply touch the screen (because it made both flippers work simultaneously rather than separately), I reconfigured it so my Droid's Back key controlled the left flipper and the Search key controlled the right.

Pinball isn't perfect - for example, moving the smartphone itself has no effect on the ball, and the games are rather simplistic. But if you're stuck on a train or in a doctor's office with nothing else to do, you could do worse than play a couple of rounds of Pinball.

The Schwartz Unsheathed

Scheff's Blend

The Schwartz UnsheathedOK, so you're not a Star Trek fan. If you're more likely to be swinging a light saber in your imagination -- and you've been envying iPhone owners their game called Star Wars: The Force Unleashed -- then here's something to keep you busy: The Schwartz Unsheathed. (Don't know about The Schwartz? It's part of Mel Brooks' satire on sci-fi movies, called Spaceballs.)

Basically, what you get is a light saber (of any color you want) against a background of stars that emits that characteristic electronic hum. Wave your smartphone around, and you get the "whoosh" sound from the movie, along with an occasional "crack!" that indicates you've made (virtual) contact with somebody else's light saber. You can even have heroic background music that plays as loudly or softly as you want (or you can mute it completely).

What does this have to do with Spaceballs? Not a thing, really. But by avoiding any mention of that S**r W**s film, perhaps the creator of this clever little app won't have Lucasfilm's lawyers to duel with.

Barbara Krasnoff is reviews editor at Computerworld. When she isn't either editing or reviewing, she blogs at The Interesting Bits ... and Bytes; you can also follow her on Twitter (@BarbaraKrasnoff).