Paul Slocum's website
I mentioned Paul Slocum in an earlier post when I wrote about his Atari Windows GUI. A lot of his work focuses on video game hacking, particularly through music. One particular piece, Combat (right), was actually exhibited at the 2004 Liverpool Biennial. It's another hacked cartridge in which the music is all glitched up:
Combat, 3 mins
I've never played the game before but in this version, the exisiting soundtrack is replaced by a house/garage/whatever funky soundtrack!
Cory Arcangel's website
...is fashionably unfashionable. Actually, I like the design better than most websites...
There's some interesting work on there, mostly conceptual but there's a long tutorial on how to recreate the 'clouds' piece, if you can get hold of a Nintendo.
Notice the great big chip pasted to the cart to modify the programming. It would have been much easier (but less fun I expect) to hack a ROM using computers... but that would probably be illegal, I suppose.