The Google I/O developer conference sold out in 59 minutes and tickets have been going for $2,000 on eBay. But there's still a chance you can go for free - if you're good enough.

Google is launching Last Call for Google I/O, a series of 10 developer challenges that will provide tickets to 100 winners.

Starting 16 March, Google will hold daily contests until 29 March (excluding weekends) in which developers will be invited to write code for such products as Android, Chrome, App Engine, YouTube APIs, Google Maps, Developer Tools and Google Apps for the Enterprise. Developers will have 20 hours to complete each coding challenge.

"Each of the challenges will focus on one of our developer products and has two rounds," Google's vice-president of engineering Vic Gundotra writes in a new blog post. "Plan to be in front of your computers for the first half-hour that the challenge starts to complete a series of questions for Round I, which will qualify you for the main coding challenge in Round II. You will have a little over 20 hours to complete Round II."

The first contest will involve Android and start at 9am PT on 16 March. There will be 10 winners for each of the 10 challenges, resulting in 100 free tickets. Google I/O itself will be held 10 and 11 May in San Francisco.