I had previously blogged a bit about Rush, the Ruby shell. Well, now Rush must now be its own force to be reckoned with, because this presentation was NOT by Adam Wiggins, the creator of Rush, but was instead by Nicholas Schlueter, the creator of RushMate. If you've not heard of it, RushMate allows you to use Rush from within TextMate, which translates to being able to write custom commands much more easily.
He showed some neat examples, including one that auto-generates an HTML page with links to all of the RDocs for all of the RubyGems you have installed locally. I have wanted something like that for times that I was not able to connect to the InterTubes, but still wanted to do some development.
The entirety of his presentation is online here with a whole bunch of code examples that will be better than my ramblings, so you should rush over and check it out.