Google just announced that window to sign up will open today at 4PM PT and remain active through April 18th at 2PM PT. Tickets have traditionally been quite hard to come by — I/O 2013 sold out in less than an hour — so Googles trying something different this year. There arent any details on what exactly Google will be showing off at I/O this year, but the company did say that itll focus on design, development, and distribution of whatever apps developers want to create. As for when youll find out if Google drew your name for this years I/O, you wont have to wait too long — the company says itll update you on the status of your registration around April 21st.