A while back, my friend Rich Vreeland, AKA Disasterpeace, made a Flash game called January where you catch snowflakes on your tongue and each plays a soft, pining note. Rich has been busy lately making music for other video games, but he just pushed out a big update to January. The new version trims down on the storyline in favor of a more capable music generator. It has auto-pilot functionality, a selection of keys to choose from, a pentatonic mode, and the ability to save your generated compositions as MIDI files.
Check out the new version of January and the original version.