Last episode of Cowboy Bebop.... ofcourse it only becomes awesome once you've watched the rest of the series... just makes you go WOAH....
and ofcourse the Full Metal Panic Fumoffu ep where Tessa comes to school... choked on my ramen and almost puked while watching that, then I couldn't stop laughing, had to watch it a couple times before I could control myself long enough to watch it all the way through...