Hat-play can be a big part of slapstick comedy -- you can imagine that trope in the hands of Laurel And Hardy, right? Or Chaplin? Two many hats, too many heads, the wrong hat... the wrong head...
And sometimes this 'hat' business carries over into contexts where it isn't funny; the Freudian 'latent content' of hat as fetish object or dreamwork symbolism comes into play and all those bowlers and fedoras and boaters start seeming unheimlich and surrealish.
This list is for when that happens. Suggestions welcome, but I'm going to be very tight-assed about what I include.
The Unbearable Lightness Of Being
The Italian Straw Hat
NOT IN DATABASE
Una Giornata Ventosa