You are not going to find much of a "party scene" for 20 somethings at WDW. There used to be comedy and dance clubs, but those closed 2 years ago. Jellyrolls could be a place to spend an evening ($10 cover), or else I would try Raglan Road if you are OK with Irish folk singing, that kind of stuff. Others have recommended Rix Lounge at CSR, they have live entertainment but most of the clientele is probably going to be conventioners. I have heard Paradiso 37 at DTD doesn't have that much of a nighttime scene but that may not be the case every night.