As part of Nycto, I’ve built a fairly nice collection of audio effects and oscillators, mainly ported from C++ and Pascal sources over at http://www.musicdsp.org. This is a simple test to show off some of the things you can do with it thus far – the reverb (based on the reverb in ChucK) and EQ are particularly useful.
Source for the whole thing is in Google Code here – it currently converts everything from stereo->mono, but I’ll be working on getting it all working in stereo soon!