Try some of the Tom Yum soups. They are sour and spicy--absolutely delicious. Usually, they are served in a metal bowl with a chimney of sorts running up the the middle. At the bottom of the chimney, they usually put camp-style fuels (FFS or "flaming fuel stuff" according to my co-worker) at the bottom of it. They light it up, and you get an impressive pyrotechnic display with your soup. It keeps the soup hot, and it's downright impressive.
With most dishes, you can ask the kitchen for mild spiciness if your tastebuds aren't up to the challenge. Thai cooking rivals Mexican cooking for spiciness.