To be honest a lot of the events around town are not that important, more returning to the house at certain times / paying attention to your main 3 NPCs. Amidst the groping scenes in the first couple weeks, theres the treehouse events like getting the roof / building the walls, and collecting magazines with Kenji (the male friend). Some of them are timed to activate at a certain day / how far you've progressed, such as the swimming event and courage test.
Depending on how far you've gone with each heroine, the later events will give you an option to choose one and have sex with them (i.e the festival where they're wearing yukatas). The older heroine's events also advance later on from groping to her being asleep, to others such as her being wasted at the end of the night (first pajamas scene), which then spurs on further events. The younger one (Yurika, IIRC), has the first sex scene in the treehouse, which you can actually get before the popsicle event (unlocked in the house after 4-5 groping scenes and having her accompany you in the house). If you find close to all the events by the end of the game, you get the boobjob, Kenji walking in, 4P, then pregnancy end on the 30th day.
I never did find out how to go out at night again, though. That's pretty much the only scene I haven't gotten naturally.