An awesome web-based took that Chris from Asmadi Games recently brought to my attention is Infinity Jukebox It finds all the identical audio moments in a song and maps them to other identical moments. The circular representation of your song is a whole new way of looking at music too. Its like suddenly having another dimension of music available.
As the song plays, it randomly takes these branches to link together other sections of the song that normally wouldn’t connect. What you get is a endless loop of version of your favorite songs. Some songs work better than others. Daft Punk songs tend to warp seamlessly. Other songs are pretty random and remix-y. This is a great tool to help you come up with new melodies. Load up a melody you’ve created that regularly returns to the same note and you’ll see how it can be rearranged.
This track from RobKTA is a great example of how it can give you cool ideas on how to re-arrange the melodies and composition of a song.
BeatScribe 