I was in colombo 2 months back with my friends , its a short trip , take ur air ticket reach colombo get free on arrival visa , go out you can directly go to hotel instead of booking through travel agent, colombo airport is little far away from the city , you can find hotel car’s outside or get a taxi ask him to get to a decent hotel tell him the budget you can offord , , usually travel agent charge as twice the rates compared to the hotel they offer , going with wife go to kandy to enjoy the hill station , negembo to enjoy the beach, for bachelors - dont go to karoke bar , if you need a female company to drink with you and u got lots of money to spend karoke is a nice place to enjoy with drinks and live music, must go to liberty plaze , its a huge shopping place with lots of entertainment zone.