[Ticman]

How about the "sword fight" scene Raiders of the Lost Ark when Indiana Jones uses his gun instead? That was awesome.

http://www.youtube.com/watch?v=1cdYrBsWhtk

Love that scene. Harrison Ford was supposed to do a huge elaborate fight scene but just drew his pistol and shot. The sword guy went with it and the rest is history. Some of the greatest movie scenes were adlibs.