As if the guys over at Youtube couldn't get any craftier with the addition of random ponies prancing around when you search "My Little Pony", it looks like they took it to the next level with customized header bars for just about everyone. Each pony from the mane 6 to Doctor Whooves has a theme. This is the best easter egg ever I think.
Simply search the pony name and you should get something for it. Some need to be a bit specific (Princess Luna instead of just Luna). And a few ponies don't have one (Cloudchaser, Daring Do)
I've messed around with a few more well known characters from other geeky movies/shows and had no luck repeating it, just in case it was some automated script. It could still be, but it's a damn good one if it is:
|Vader < Ponies apparently|