I just stumbled on the Java 4K Game Programming Contest. This looks like an excellent contest for programmers out there trying to get into the video game industry or just trying to prove their hacking skills:
The Java 4K Programming Contest is the ultimate byte-squeezing Java challenge! Using only 4096 bytes, competitors use every trick up their sleeve to create an entire game. The current Java 4K is running from December 1st, 2005 – March 1st, 2006.
I really like the size limit. In the good old days, we really just had 4KB of internal memory. I programmed a few cool games back when computers still had green on black screens, including a full Othello implementation (including the AI), and it ran very well on probably less than 4K.
And I think 4K ought to be enough for a great game prototype. Myself, I would try to do it without using obfuscated code and try to get points for programming elegance.