try a $10 radio shack *shudder* mic...
or get one of those 18Litre water jugs from a water cooler...cut the top off, put a small hole in the bottom, insert the mic in the bottom, and let the good times roll...look at me mom, i'm singin into, well basically a giant cup!
works better with an omnidirectional mic....but well, maybe that's too crazy for you...