I'm done... now what?

You just finished a sprint. Whether it be a single feature, a set of features, or even a release. You were test-driven, user-accepted, and agile, and now you have no juice left. You don't have the brainpower to start working on the next thing on your task list, but you probably can't just decide to go home at 2 pm, either. :) So what do you do?

Document what you just did! Assuming, of course, that you weren't documenting along the way, put everything you know about what you just did in some sort of documentation — whether it's in a wiki (hi Trac!) or some other documentation repository. Write about it while you can still remember it, and you'll thank yourself later.