Activities:

searching up scary stories and telling them in the dark

orr they watch a horror movie (does one person get really scared?)

spilling secrets and gossip left and right

playing truth or dare, kiss marry kill, smash or pass, 7 minutes in heaven, spin the bottle etc

hyping eachother up to stay awake all night but passing out anyways (in eachothers arms?)

hanging out with eachother but towards the end, everyone is up scrolling on their phones late at night, just existing next to eachother

prank calling people!!

doing blind karaoke and laughing at how ridiculously wrong everyone is

making popcorn and watching a movie, but in the end either nobody is paying attention or everyone is completely invested

orrr i raise you - they make a movie of their own, filming on their phones and laughing their asses off

someone falls asleep first and gets pranked

Facemasks!!

eating a bunch of rubbish and falling into food comas

that one point where everyone is sleep deprived and suddenly speaking their deepest thoughts, blankly staring at the ceiling (maybe its just your otp talking and one person who they thought was asleep catches them confessing!!)

making a late night snack run/fridge raid (mcdonalds?)

being really loud and waking neighbours/parents, who come tell them to shush (maybe half of the otp is the annoyed neighbour?)

Just dance

Sleeping:

people might have to share blankets and therefore need to scooch closer together

everyone sleeps in different spots (couch, floor, mattress, dog bed if they're desperate etc)

someone ends up sleeping on the floor because of someone else taking up all the space

someone sleep-talks gibberish or snoring late at night, scaring the others

a bunch of people sleep in a cuddle pile

the appointed parent character might look fondly at the others as they sleep

someone latches onto someone else in their sleep, trapping them in their place

The next morning:

everyone waking up the next morning absolutely sleep deprived and cranky but regretting nothing (and looking like they'd been through a rough break up)

someone wakes up first and doesn't know what to do with themselves

someone wakes up to make coffee at an insanely early hour

Things to consider:

Who upholds their complicated nighttime routine and who loses all sense of hygiene?

Who forgets their clothes so they need to share with another character?

Who makes breakfast for everyone in the morning?

Who wakes up at an insanely early time and who sleeps in insanely late?

Who snores/kicks in their sleep?

Who tucks in the sleeping characters?

Who is scared of a horror movie/story and who coaches them through it?

Who falls asleep first and last and who falls asleep last?

Who wakes up tangled in eachothers limbs and who takes a picture before they wake up?

Who chides the other characters into getting the sleep they need?

Who prefers to sleep alone and who likes sleeping near other people?