Circa '97 me and the guys used to chat about our ideal setup for playing video out in a club to accompany the DJ. We'd have video sequences and realtime animations which reacted to the music, we'd have a bunch of computers and someone "flying" it, it would be amazing.
Considering that the fastest machine available at the time was a Pentium 200mmx and nobody except SGI had thought to put the words "3d" and "hardware" in the same sentence our options were limited to say the least. The concept of VJing was itself unheard of, the closest thing we'd heard of

"Moppi Demopaja is a demo authoring tool. It has a interface similar to the popular 2D animation tools such as Macromedia Flash and Adobe After Effects (I hope they don't have any patents on their User interfaces). Many of the user interface functionality is imitated from After Effects." Quote from the website
Demopaja is very good for making (not only demos, but also) footage, or you could use it also in realtime (worx fullscreen 2) but it doesnt have any realtime controllers for the user... but it has a free SDK for c++... so maybe...

Features:
- Play Flash files
- Play Images