A must for Sonic fans old and new. Contains a lot of resources, including a forum and a fan games section.
A classic! No longer being updated as far as I know. Tons of funny flash cartoons here, even a few games! One of my all-time favorite websites from the good o’l days of the interwebs.
Another long-time favorite of mine, this site has a huge archive of midi songs from video games across several platforms and generations.