Kung Pao Enter the Fist. Warning: you must be immature and somewhat comfortable with jokes that might not have aged well. I haven't watched it since I was a teen, but I remember thinking it was hilarious back then...
A younger friend of mine had started playing the Evil Dead game with some of his friends but had never seen the movies. I'd not watched them in years, so I invited him over to marathon them one weekend. We drank, ate pizza and did the whole trilogy, and we had an absolute blast. He loved how different each movie was, especially Heart of Darkness. How each one gets sillier than the last.
A few months later, Evil Dead Rise came out in the cinema, so we had to go see it. While this was much more a straight up horror movie (with a small amount of the Evil Dead silliness), I still enjoyed it (I find horror movies quite funny, like an emotional rollercoaster), but he was hiding behind his coat the whole time, terrified of what was happening on screen. That made it even funnier for me.
Fully expecting flak for this, but Uwe Boll's Postal. It's a gross, idiotic movie with awful taste, and it's not so much that it hasn't aged well, it's more that it was made awful on purpose. that's also what makes it perfect for schlock movie night.
if you've played any of the Postal games, you know what to expect in terms of tone. if you haven't: GOOD. Don't.
Nudist Colony of the Dead is awful and fantastic at the same time. I love getting a friend to go into the movie blind.
Tap for spoiler
It's fucking hilarious watching someone slowly realize that they're watching a super low budget movie musical that's a musical about a bunch of religious types getting murdered by 'nudist' zombies (that basically have the equivalent of fig leaf clothing).
The day I got my best bud fucking blazed out of his mind to watch it has to be one of my favorite experiences.
My top series for this is "Hi-sCool SeHa Girls", a 3D anime about three Sega game consoles who have been anthropomorphised into highschool girls. they go on adventures inside of lesser-known sega branded games, and the episodes are a mix of legitimately funny visual gags, good storytelling, bad storytelling, and both decent-quality cgi and extremely low-quality video editing. It's the most fever-dream-like show I've seen.
Garth Marenghi's dark place, rifftrax/mst3k, Young Frankenstein, duck soup, Joe Bob's has a bunch of shlocky horror movies mixed in with classics they do intros and interrupts like the old public access/cable monster movies
Definitely wacky cartoons like Adventures of Sonic The Hedgehog or maybe season 1 of Reboot (part way through season 2, so I don't know whether the rest of the seasons are as light hearted as season 1), both shows you can laugh at the obsurdities of it all and in Reboots case laugh at the very outdated animation.
Hilariously dry comedy with the late Val Kilmore as a sassy gay man. Every other movie I wanted to suggest was already posted here. These are all great choices!
In Olympus Has Fallen, North Korea invades the US 🤭 Absolutely ridiculous, but fun to watch. (Maybe not that ridiculous tho, considering the current administration's incompetency 👀)
If you haven't seen Angel has fallen - rectify this immediately. I'm fairly certain that Nolte just wandered on set wearing his own clothes and they were like, "Great! Let's shoot!"