"the post-credit sting"

Film Gary Bainbridge's column in the Liverpool Post about seeing The Avengers is delicious. No spoilers:

"I find it virtually impossible to leave a cinema before the end credits have finished rolling. This is not because I am particularly interested in the work of the American Humane Association – although I fear their evil counterparts, the American Inhumane Association.

"It is because of the post-credit sting. I saw Ferris Bueller's Day Off at the cinema and went home before the credits finished rolling."

"You're still here? It's over."