Need help for senior prank!

The prank we are trying to pull sounds simple enough. I have a 5.1 digital surround sound system(http://www.newegg.com/Product/Produ...Froogle-_-Speakers-_-Logitech+Inc.-_-36121006)

What we want to do is make something to plug this into and place it in an empty locker at school. We are going to play funny voice clips VERY LOUDLY at random intervals during class periods.

What we are stuck on is the "power" issue. We have nothing to plug it into. I was wondering if anyone here had some suggestions on how to "plug it in" (Battery Powered?). We have a fairly low budget and would like to have it be as discreet as possible.

Any other suggestions or modifications to this plan would also be fine.

Thanks much,
2legit

 

even if you could power it without plugging it in, you would need a locker full of batteries, which would require a very large budget.

oh, and what timw said. sorry.