funnily enough, I've also been up for more than 24 hours
i don't exactly plan things for staying up, but drawing gets me focused on something and therefore I don't fall asleep, maybe it could work for you
i also play roguelikes which for some reason prevents me from falling asleep. usually when 4 or 5 pm comes I take a pill to fall in an even deeper sleep.
just don't do anything that barely requires any focus or just, not any focus at all. like browsing the forums or watching tv