For programmers of a certain age - those who saw their first internet connection in the 90s - MUDs [Multi User Dungeons - basically D&D online] were de rigueur. Open Source was in its infancy and this new thing called linux came on a stack of 35 3.5" floppy disks (configuration was equally hostile). So if you wanted to contribute to a collaborative project MUDs were where it was at. A number of python people have outed themselves as [ex?]mudders, including Glyph (Twisted founder, Twisted started as a mudlib), Doug Napoleone (PSF board), Jesse Noller (PSF board), Richard Tew (Stackless Python), Will Kahn-Greene (Miro, and mud client Lyntin), and yours truly (I maintain telnetlib, need I say more?).
Learning is in the doing, so what I got of college was mostly lots of free time to do stuff. I spent maybe 400 hours in four years doing programming for classwork and over 4000 hours writing LPC code for a now defunt MUD* (using /bin/ed - the only supported editor). Writing a mudlib was my "turtles all the way down" moment, when it clicked that user level programs were just programs that were composited from other programs; The trick was that the lower level stuff had an agreed upon naming convention but otherwise wasn't special at all.
I'll admit to being somewhat jealous of the college students of today - it is easy to contribute to projects that actually matter. Being able to rely on ping times being under 500ms is nice too (Europe used to just _go away_, sometimes for days).
I haven't left MUDing completely behind. I still use it to try out new methodologies in coding and just play around in general. Leanlyn (http://bit.ly/leanlyn) is my Lyntin fork that is about 10 years old and will never be finished (or be less than user hostile).
* The dead mud was Ether Realms. I can still be found sometimes at OverDrive (a Lehigh staple) and Three Kingdoms.
** College came with lots and lots of free time. I spent way more than 4000 hours just chasing tail. Imagine me but with shoulder length hair, an eyebrow ring, and a flannel shirt (it was the 90s)