My son, who is 20, will be coming over for enchiladas and orange chiffon cake tomorrow. Yay!
I would like some suggestions as to perhaps a very, very funny movie, or else one that is really cool. We both love science fiction, but there aren’t many we haven’t seen. He has already seen The Blues Brothers and Nacho Libre, two of my favorite funny movies. I am drawing blanks.
Thanks all!
I make no promises, but, “Cockneys vs Zombies,” is a funny horror flick a la “Shaun Of The Dead,” not quite as good as SOTD, though.
I’ll just base these on the two movies you mention.
How about funny sf (well, it’s kinda sf): Buckaroo Banzai (I like both of the movies you mention, so I thought this might be something you’d appreciate)
Jack Black plus music gives you… School of Rock.
Very goofy funny with silly sports references: Dodgeball.
I’ll recommend “Shaun of the Dead” 
Galaxy Quest
Ding!
Winner.
I just watched this movie on Netflix, I thought it was pretty good. It’s called Danny Deckchair. It’s about a guy who accidently flies away in a deckchair attached with helium balloons. It sounds kinda stupid but it was actually pretty good.
Get Him to the Greek funny, but lots of excess on the part of some of the characters (which is what makes it funny)
Blazing Saddles, Animal House, and History of the World, Part I are all great comedies.
This is the End was pretty funny. I actually think it’s funnier than all of the above comedys.
The Producers is funny.
Zoolander
With that handle do you really have a choice?
Wait a minute–zombyWOOF, …wonder MUTT? DADDY!! I KNEW YOU’D COME BACK!! 
The funniest movie I’ve seen in a long time is “The Birdcage.”
But for comedy + sci fi, I agree with “Galaxy Quest.”
I like it, but if you can find it the documentary is 100 times better. It’s about Paul Green, who started Paul Green’s School of Rock, whipping a new class into shape to play a Frank Zappa festival in Germany, where they get a standing ovation from the kind of huge Zappa fans who would attend a Zappa festival in Germany. It’s fun, funny, fascinating and kinda awe-inspiring.
I may be biased since my husband and I video School of Rock shows and as I’m typing this I’m hearing the Oak Park SOR do a sound check prior to a Doors and Beatles show. We did 6 shows yesterday (we were at the venue, which was horrible, for 9 hours). I have to defend and advocate for the REAL School of Rock movie.
2nd too for Galaxy Quest, Buckaroo Bonzai and Shaun of the Dead, and add Tropic Thunder. If he likes bent horror he’s probably already seen Tucker & Dale vs. Evil, and Cabin in the Woods but not, those.
Scott Pilgrim vs the World.
Life of Brian.
Many people seem to feel very strongly about Zombie movies. They either really like them or they really hate them.
I used to hate them all. I never saw one that was enjoyable. But then I saw one starring Sarah Polley.
I don’t know if you know who she is. But, IMO, she is an extremely underrated actress.
There are only two half decent zombie films I have ever seen. One is Dawn of the Dead (2004) with Sarah Polley. The other stars Woody Harrelson. It is Zombieland (2009) and it is a lot of fun. Really and truly - A lot of fun! It also stars Jessie Eisenberg, Emma Stone and Bill Murray.
I predict that if you show him Zombieland, he will look at you and say, “Gosh Mom! I never knew you could be so cool!”
Anyway, Try it! You’ll like it! Bill Murray is way cool!
P.S. Am I correct in assuming you are his Mom and not his Dad? It was just a feeling. It’s not really important and I was just curious.
Repeats of many already mentioned.
“GalaxyQuest” is always a good choice.
“This is the End” is good, if you are aware of the current celebs and such.
“Shaun of the Dead” and “Hot Fuzz”, both with Simon Pegg and Nick whats-his-name.
“Tropic Thunder” is much better than I thought it would be. Just goofy.
“Dodgeball”. But that’s in no way Sci-Fi
Binge watch streams of Key & Peele …they always amuse me. Not every skit is a hit, but generally a good time. And again, not Sci-Fi.
I think I must be one of the few that enjoyed it, but if you liked stuff such as “Kentucky Fried Movie” and “Amazon women on the Moon” you just might like “Movie 42”. It’s just plain stupid skits, but sometimes one is in the mood for stupid fun.
P.S. If none of these movies appeal to you, you can always show him what I think is the funniest movie ever made. It is Dirty Rotten Scoundrels (1988). It stars Steve Martin, Michael Caine and Glenne Headly.
It is not Science Fiction. It is a humorous kind of crime caper / love story.
There is also “Airplane” - a cheap kind of slapstick (but not really) comedy. If you have never seen it before, it’s always good for laughs. Even if you have seen it before.