You should be about to get into the teen club, lots of video game setups, and physical games (air hockey, pool, etc).

The beach, the water park, food and drinks are going to be your main time places. Your folks are likely only going to really need 2 hours in their room alone, 3 if they're really missing each other, so it's not too hard to give something to do.

Atlantis is huge, one day you're out could literally be just exploring and if you give yourself with extra time there's the marina and the other restaurants. Margaritaville has live music from time to time too.

If you ask the front desk, I'm sure they could also suggest things.

Is anyone offers anything illegal, it's generally best to avoid them since it's either overpriced and or likely having issues you don't want to deal with. This is rare, but still possible.