I have kept the Florida Worm Lizard (Rhineura floridana) also known as thunder worms. They are seen at the surface after a rain. This is the only dealer I have seen that sells them:

http://www.johnkoerner.org/ExoticOddities/worms.html

Doesn't look like he has any in stock however. I have heard that they are hard to keep but the one I had lived for five years and seemed quite hardy. I did check the PH of the natural substrate, which I had a sample of, and matched it. It was alkaline 7.8 . I also create a false bottom with egg crate and screen to keep the sand/soil mixture well drained. The tank was a 10 gallon and an external heating pad at one end was used. A variety of food items were taken, basically any small insect or worm was readily eaten.