The best i can come up with is to write something cool in lisp and show it to them. And by "cool" i don't mean a lame example snippet showing off closures, or a

The best i can come up with is to write something cool in lisp and show it to them. And by "cool" i don't mean a lame example snippet showing off closures, or an implementation of an "unless" macro, i mean a real app. Not too big(because it will take you longer to write, and also it will be harder to explain all the details to your friends while showing them your code), but not too short(its easy for languages like python or ruby to have shorter versions of very small lisp programs, so you might fail to impress if your app is too trivial). If you just want to "geek out" on them and spit a lot of hype about lisp, that might not be a good idea. Its good to educate yourself about lisp and other languages, and be ready to answer questions, and explain your choice, but IMHO its better to show lisps power with real code.