This has been covered on HN before (IIRC that's where I first read about it), but my favorite vision color "trick" is the McCollough Effect, mostly because of h

This has been covered on HN before (IIRC that's where I first read about it), but my favorite vision color "trick" is the McCollough Effect, mostly because of how long it lasts (weeks in my case, YMMV): http://www.cheswick.com/ches/projects/me/ http://www.cheswick.com/ches/projects/me/