The PC Subwoofer
 

How many useless PCs do you have sitting around? Whether they're too old and slow or simply stopped working one day, cast-off tower and minitower machines are a plague on the land. So I decided to repurpose one by stripping it to its essential form—an empty box—and rebuilding it as a self-powered subwoofer. This is an inherently bad idea. Metal clangs and vibrates; speaker cabinets should be nonresonant. PC cases have more holes in them than the Godfather's enemies; speaker cases need to be airtight. Metal is inconvenient to work with; wood cuts easily.

None of those practical considerations matter once you get the burning desire to mod a PC case in a totally unusual way.

http://www.extremetech.com/article2/...2103155,00.asp