Scrambled Hackz is an extraordinary piece of software which analyses any audio input (particularly singing or human beatboxing), and crudely recreates it using clips from another piece of music (it uses videos as a source, so the video clips are remixed at the same time). It's like an instant live remix, with a microphone as an interface. It's hard to explain, but creator Sven König does it very well in this splendid promotional video (unfortunately a rather slow download). Sven has used the software as an instrument for live performance, but also as a very funny art installation, which lets people sing into a microphone and watch their singing recreated (sort of) by MC Hammer. The software itself isn't yet available for download, but will be soon. Another cool project by Sven is Appropriate, also a video remixing thing. (Thanks, Marcus)
UPDATE: The video is now on YouTube (also here)