Google has announced Last Call for Google I/O, a contest offering 100 chances to win tickets to attend the now-sold-out Google I/O 2011.

As we commented in February Google I/O 2011 sold out in under an hour and given that tickets were just short of $500 this is evidence of real commitment and enthusiasm.

Many would-be attendees were no doubt disappointed but there is still a chance to be at this year's most coveted event - by winning a free place!

From March 16  there will be 10 days of challenges, each focussing on specific products, with 10 winners on each day.

This timetable shows the products and starting times (PDT): 

•   March 16 - Android, 9:00 am
•   March 17 - Chrome, 9:00 am
•   March 18 - App Engine, 9:00 am
•   March 21 - YouTube APIs, 9:00 am
•   March 22 - Game Developers, 9:00 am
•   March 23 - Google Maps / Geo, 4:00 pm
•   March 24 - Commerce, 9:00 am
•   March 25 - Developer Tools / GWT, 9:00 am
•   March 28 - Accessibility, 4:00 pm
•   March 29 - Google Apps / Enterprise, 4:00 pm

The contest is open only to developers in the 50 United States and the District of Columbia. Each of the challenges has two rounds. Participants should plan to be in front of  thier 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 then have a little over 20hrs to complete Round II. 

You can enter in multiple challenges but only one submission is allowed for each and they are for individuals - no teams are allowed.  Winners will be announced on April 4.

For more information and contest rules, visit the contest site.