If you use Twitter, you'll probably have seen this already because it's one of those trending things... If you don't tweet or twitter or whatever, check it out. DJ Morgoth of Germany ("more goth" from Germany? What a surprise.) has mashed up "Smells like Teen Spirit" with "Never Gonna Give You Up." If this brings back the rickroll, I will gladly support it.
Watch and be amazed at how well they sync: