Actor Allusion: All over the place. All of the stars are represented by their hobbies. For instance, Paul Newman is in a racing wheelchair (at the time, he was car racing as a hobby).
Probably the best Actor Allusion is when the only spoken word of dialogue in the entire movie comes from a mime.
Aluminum Christmas Trees: Ha ha! Ashtrays INSIDE by the elevators IN A HOSPITAL! That's funny! Actually, what's funny is that wasn't a joke - it was standard realistic set dressing for a hospital set in the 1970's.
Letting the Air out of the Band: Over a still photo of New York City, the orchestra plays "San Francisco," only to have the conductor (famous movie maestro Lionel Newman) cue them out, instruments trailing off in the process. With a tap of his baton, the orchestra switches to "We'll Have Manhattan."
Mistaken for Gay: Funn, Eggs, and Bell are subjected to this twice by the same duo of women. That said, they were essentially dry humping each other in public the first time.
Murphy's Bed: Various gags during the motel scene; the trope is also lampshaded by a sign at the motel itself.
Featuring Murphy Beds: Charming to the unsophisticated.
No Celebrities Were Harmed: Averted; not only do the various celebrities in the movie cameo as themselves, but they are portrayed in a caustically self-parodying way; Burt Reynolds in particular is presented has an immense Narcissist, who stops before mirrors to strike poses and has a giant billboard with his name and photo on his house.
A Simple Plan / Zany Scheme: Parodied; the absurd strategies Mel and his friends use to contact the stars and get them to play in the movie always work. When they use a straight approach, it always fails.
Though it appears that Burt Reynolds at least only agrees to do the film so they'll stop bugging him.
Something Else Also Rises: When the Engulf & Devour boardmembers are shown a photograph of Bernadette Peters (again, Yummy), as the woman who would be sent to seduce Funn, the table they're sitting at rises several inches.