I too have been to every I/O, but the only year I ever got dibs on tickets was '10. I believe that '10 attendees who solved the puzzle on the t-shirts they gave

I too have been to every I/O, but the only year I ever got dibs on tickets was '10. I believe that '10 attendees who solved the puzzle on the t-shirts they gave out got dibs for '11, but I know of nobody who got dibs for '12.