Microsoft is conducting an Game Development competition, DreamBuildPlay, with a closing date of 2 July 2007.
I attended Microsoft's events at GDC and got to see the games the 4 teams built in 4 days. Quite impressive - simple but still fun.
Take a look at the following article, and follow the link to www.dreambuildplay.com and let me know if you'd like to join. I strongly encourage you to sign up for this.
I also attended MS's hands-on session for XNA Game Dev. As you might know, XNA uses C#, so if you're comfortable with Java, you should be able to start building real quick.
You can sign up for this as individuals or as a team effort. As the closing date is in July (closer than we feel), I suggest kick starting development ASAP. Think of an original game concept and start working on it for the Windows platform. If you do decide to port over to XBox 360 (which is quite simple), we can test it out using a Creator's Club license (which you don't have to get yet).