One thing not to be missed is seeing Bangkok from the river. Travelling on the boat is a good way to cool down and offers a different perspective on the city.
You can hire your own boat to explore the river and canals or simply jump on the Chao Phraya river express boats, they come about every 15-20 minutes. This is an easy and cheap way to get to some of the major sights of Bangkok, such as Wat Pho and the Grand Palace. Click here for a Map of the river express piers and the different types of boat that operate.
The skytrain and underground are cheap and quick ways to travel, the trains are about every 2-3 minutes. These 2 options are always quicker and more reliable than travelling by road. See the seperate pages for each on the left menu. The roads of Bankgok are always busy, often gridlocked. They are also poorly laid out and maintained, traffic is bad even during the daytime. In the peak rush hours it isn't advisable to go by road.
As a tourist the river, underground and skytrain are the best ways to go. During the daytime a ride in a tuk tuk is good fun, but settle your fare before getting in. All taxis are metered.