You want to give the crowd a WTF moment? Check out Dick This! by Dick Brave & The Backbeats from Germany. 50% of the album is traditional 50s rock, but the other is covers of non rockabilly music. George Michael, Michael Jackson, Pink, Red Hot Chilly Peppers, Aerosmith, etc... Really.
http://www.youtube.com/watch?v=X0FyFgEHuiQ
Really cool spoof of the Run DMC/Aerosmith collaboration from the 80s.
I was in Berlin in 2005. I hadn't watched any TV in about a month, so I flipped on MTV Europe for a Vincent Vega moment. (They got the same E30 M3 we got here, cept over there its just... a little different.) In between a constant rotation of 50 Cent and Gwen Stefani-literally EVERY 10 songs, I caught that song. I bought the album that day. Pure bliss the day I got home and listened to the whole thing.