Many of us have a touch of synesthesia — seeing numbers or hearing musical tones as colors, thanks to a lucky bit of crossed wiring in the brain. Many commenters on Vilayanur Ramachandran’s TEDTalk talk engagingly about their experience with it. Want to know what it feels like? Try this: a synesthesia generator >>.
It’s a feature of the hypertext exploration site Hypertextopia. And yes, you can change the colors — so if you see A as white and C as green, but your brother insists that A is red (because, as Ramachandran points out, synesthesia runs in families, but no one has it in exactly the same way), just click the row of letters below the text window.