The most recent announcements will be listed first.
CSE/ENGR 142 did "Slack Man" as a project last year. The code is probably completely useless for this project (it uses GP142, and is not object-oriented). But you might find some ideas there.
Check out this Pac Man site. There are probably many others.
If you do find code that you want to use, remember two things: first, you MUST credit the source, no matter how much you end up modifying it. Second, the version you turn in must be a recognizable descendant of the code you are given to start with. It can't just be a completely different program that bears no relation to the starting code.