This is my new favorite hobby.
LinkOnce you've selected your emulator and ROM (any console will do), you'll need to set "Start byte" to a hex number between 1000 and FFFF and check the "auto end" box. Next you'll want to set the "Corrupt every __th bytes" box to a (decimal) number between 500 and 4000. Select your corruption method, and play some
Sonic the Missingno Super Missingno Brothers!
EDIT: PLEASE don't post your corrupted roms here!
EDIT 2: BBcode fail