It picks up about £40-50 on eBay these days, and there's a good reason why. It's fantastic. It's mental. I've never done acid (shame on me), but the guys that made this must have been (shame on them). And you probably want to (shame on you).
Pictures don't do it justice, so here's a youtube video of someone caining it. Rez that is. Area 5 - starting somewhere in the middle...
Oh, I made a wallpaper too, you can download it by clicking here.Preview below:
EDIT: Also check out this interview with one of the members of the team that brought you Rez and Space Channel 5 here!