I lived in Jakarta for a few years. There isn’t much going on in Jakarta as such. There are some decent clubs and nightspots and depending on if it’s a lads night or not some Bangkok style entertainment (malioboro). Just not during Ramadan, everything closes down.
I can recommend a couple of things, not requiring you to jump on a plane and are quite nice but really depends on what you want to get out of it.
If you are looking for something chilled, beachy and quite tranquil I’d recommend going to Tiger island (in the thousand islands) it’s a boat ride from Jakarta. You can relax, go swimming, snorkelling or even scuba. I can send you some details and a contact if you wanted to know more.
If you wanted something a little different and to somewhat see some rural parts of Indonesia there is a farm stay down in Bogor (about 1.5-2 hours south of Jakarta). You can go whitewater rafting among other things. Host is a westerner, forget his name but he’s nice. Link here:
http://portibi.com/
If you want to get on a plane and are after a cultural immersion - you should check out Yogyakarta and maybe head out to Borubudur.
Otherwise Manado and North Sulawesi is pretty nice too.
Anyway good luck man, enjoy and have fun.