We've had an eye on 'mindbending rave platformer' Circa Infinity for a while now, so it's great to hear a demo has been released for everyone to play. If anything, it'll help you understand the concept of the game.
If you don't want to play the free demo, creator Kenny Sun has also uploaded a speedrun video for your enjoyment. Who needs playing when we have watching?
Seriously, with this and the embeddable DOS games today, I really will struggle to be doing much actual work. Oh, and Circa Infinity is still looking for Greenlight love, so if you play and enjoy it - or like the look of it in the video - think about giving it a vote.