I just have a ball messing with the filters on my Droid's little camera app. It's called FX Camera. I'm not sure if I've said the name of it before. A lovely lady I know was talking about the Hipstamatic (I think that's what it's called) app for her iPhone, and I went in search of the equivalent.
Oh, and the application brings out different hues, which is awesome. This one makes my eyes look reeeeaaaaally creepy green. They're fairly creepy green anyhow, but not that bright.
Anyhow, free camera application. Check it.