Maybe not one of the most common thing for tourists to do for dinner (but it should be!) is to go on a river cruise. 

There is a day-long tourist boat ride, but the best idea if you don't have a whole day to spend on a cruise is the dinner cruise offered by the famous Riverside Restaurant. You pre-order your meals and arrive by about 7:15 and depart for a 75 minute cruise. At 8:00 they will prepare the meal fresh and you will eat while boating up and down the Ping River. It costs a couple baht more (45-90baht per head) to eat on the boat but it certainly has proven to be very popular with family gatherings and pre-wedding parties alike. Riverside restaurant