Bond Bar is a trendy lounge at the Cosmopolitan with DJ music and a hip scene. Even when other places are pretty much dead, this place is kickin'. That being said, it can be pretty frustrating to get a drink when it's packed (alternative: go across the way to the adjacent bar and order drinks there and bring back).
For some reason, we happened to be there when the DJ was spinning old school 90's hip-hop so we clearly dated ourselves as we and the 30-something crowd were feeling the vibe while and the 20-something quickly left in a huff. :)