There is a Thai international travel fair at the Queen Sirikit Convention Center which will open to the public on Saturday, March 1. I don't know yet how long it will keep going.

The Queen Sirikit Convention Center is located on Asoke-Ratchadapisek Road near the intersection with Rama 4 Road, and there is a subway stop right there, the Queen Sirikit station.

There's also a nice park there with a lake, where you can rent a bicycle or a paddle boat.