All night in Colombo, Sri Lanka

Hello out there! My travel partner and I are going to be landing at the airport in Colombo, Sri Lanka at about 1am and we have a train out to Kandy at 7 a.m. We do not feeling like paying for a hotel room for a few short hours....Does anyone have suggestions on what we could do all night? (Well, for 4 hours). It will be a Thursday night. Restaurants, clubs, casinos, a spa (where we could catch a snooze with a normal massage)?