Turn up your speakers, aiight?
I read this in Wired online - possees of computer science grad students at Purdue and Stanford are engaging in hard-core verbal warfare around topics as contentious in the streetz as quantum cryptography and C++.
Check out MC Plus+ and the Empty Set, for example.
My personal favorite, Monzy, left me laughing out loud with lines like, "I may not have a label but I rap like a star; I'm an unsigned long int and you're an 8-bit char." Check out Monzy at his website. (note! listen to the MP3 before jumping ahead and reading the lyrics.)