HTML5 Canvas + color cycling = 8-bit graphical win!
Then there's the work of developer Joe Huckaby. Joe has taken images created by graphic artist Mark Ferrari to produce some incredibly cool, animated retro gaming images using HTML 5's canvas element to reproduce an effect called color cycling. While the demos themselves are impressive, equally as impressive is the fact that they work extremely well on darn near any HTML5-compatible browser -- including mobile Safari.
You can view Joe's demos on this page -- my favorite is the one above, Water City Gates.