If you haven't heard of or seen This Is Spinal Tap, you will almost definitely have heard the immortal phrase "turn it up to 11", which originated from what is undoubtedly the funniest scene in this film, and one of the funniest pieces of dialogue in mock documentary history. Spinal Tap was and still is a parody English heavy metal band formed of David St. Hubbins (portrayed by Michael McKean), Nigel Tufnel (Christopher Guest) and Derek Smalls (Harry Shearer). Way back before the likes of The Office and the stream of documentary style comedies that followed it, This is Spinal Tap introduced us to a mad satirical world of rock n' roll excess, over inflated egos and really difficult-to-navigate corridors. It's still just as funny today as it was 30 years ago, so if you haven't seen it, check it out.