s.w.a.c. wrote:Olsen & Johnson giving away the ending to Citizen Kane in Hellzapoppin'.
Or in CRAZY HOUSE when Chic Johnson tells a Universal executive over the phone, "This is your favorite comedy team." The executive replies, "Oh, Abbott and Costello!"
Laurel and Hardy had a few in-jokes. In BABES IN TOYLAND, Ollie asks Stan, "What can you do that I can't do?" and Stan reprises the "earsie-nosey" bit from FRA DIAVOLO. In BLOCKHEADS, Stan tries to make his hand into a lighter, a running gag in WAY OUT WEST.
This may not be exactly an in-joke, but in OUR RELATIONS Stan suggests they use bed sheets to dress up as "Singapore Eskimoes" and Ollie says, "That sounds screwy to me but any old port in a storm. You've got to be right once in your life," thus summing up the entire history of L&H films.