A couple random things I've encountered over the last few days.
First, an iPhone app called "Criticals" which generates random descriptions and mechanical effects for critical hits and fumbles, customizable by weapon or spell type and type of creature. The app is put out by D20Renegade.com, which I also wanted to mention a bit.
D20Renegade.com is the home of the eponymous fantasy RPG system, which bills itself as "open-source" and is totally free. Pretty cool. Not sure I'll be able to play it with my limited gaming time, but I like the concept and hope it is successful. Go check it out.
The last thing I wanted to point everyone to is BeyondtheStatBlock.com, which is a website with the very lofty goal of writing flavor text for monster powers for every published 4e monster. You have to sign up for it, but that lets you go in and add descriptions to the list. Go on and help out!