To the tune of "Roll Out the Barrel":
Roll like a barrel,
You'll have barrel of fun!
Roll like a barrel,
And you won't get injured none!
(TCM had some short feature about 1930s stuntmen, and they show these deadly-looking crashes and such, and then they slow down the film, saying that the stuntman knows that by going limp and rolling like a barrel, he won't be seriously injured. I know the above song is silly, but it's an easy way to remember what to do in such situations.)
