Okay I dont know if this will go down aswell as damnz's "What anime?" thread, Because it takes a bit longer, But I'll give it a shot anyway.
So all you do is, use your media player to capture a sound sample of an anime OP or ED, Then upload it to a site like Sound Upload and post the link here, Then others just guess what anime it's from.
I use KMplayer to capture them, But you could just rename an op/ed that you already have and upload that.
So I'll start with a really easy one..
Download 02[(000001)18-03-53].MP3 <---- You don't have to download it, It'll play on the site.