Programmer wants to make games.

I've been taking Computer Science classes for the past couple years so I can already program in Java. I want to tool around and make games for the rest of the summer, but I don't know where to start. What language/IDE/library should I use? I just want to make 2d platformy action games and such.

>>8
Java programmers tend to think in terms of IDEs, when they could just use cat instead of Eclipses, and NetBeans, or whatever Enterprise Bullshit they are using.