What's Up, Doc?

First American film to credit the stunt people in the credits (first British film to do so was the James Bond film Moonraker (1979)).

Throughout the film Howard strikes several rocks with tuning forks, and then listens to the tuning fork as if he's expecting a different tone when he hits different rocks. Tuning forks are made to resonate at a fixed pitch, so no matter what object is struck with the fork, it will always sound the same.

The opening and closing credits are shown printed in a large book whose pages are turned by a woman's expressive hand. The opening credits conclude with the last page showing a drawing of a plaid overnight bag with the prologue: "Once upon a time, there was a plaid overnight case..." The drawing dissolves into the opening scene of the same overnight case in an airport baggage claim shelf.

Edited into The Clock (2010)