The places with some active night life are Colombo, Negombo and Hikkaduwa.
Colombo has some decent pubs, night clubs, karaoke lounges and bars. There is a growing pub-culture among the young crowd in Colombo. Friday and Saturday nights are the days for all night partying. The casinos offer a good combination of live entertainment, food and games of chance.
Negombo and Hikkaduwa have some good beach restaurants and bars. Negombo doesn’t have much of a party scene, but you will find regular beach parties in Hikkaduwa.