The pile cast (often called a parachute or puddle cast) is very useful when you are above a fish. With this cast you in effect "pile" up the end of the leader and tippet to get a longer drag free drift over your target. I have also found it to be very useful when fishing back eddies.
Pile Cast - Bumcast (YouTube)
The Parachute and Pile Casts - Orvis, Pete Kutzer (YouTube)