Couldn't sleep, so decided to invest some time into the SDK of my favorite music player. It's a DSP module, so you'll have to add it through the preferences pages in the file menu.
You can download foo_amBX here.

Enjoy!
Edit 1: amBX wiki page with installation instructions
Edit 2: due to problems the file was outdated, please download again
Edit 3: fixes
Edit 4: v0.2 released
Edit 5: v0.3 released (new: updates per second configurable)
Edit 6: v0.4 released (bugfixes, more configuration options)
Edit 7: v0.5 released (much better light mixing)
Edit 9: v0.6 released (improved mixing, better bass response, some color presets)
Edit 10: v0.7 released (tweaked color presets, added spectrum presets)
Edit 11: v0.8 released (configurable temporal buffering)
