Micro worms, Banana worms and Vinegar worms. There are others, but those are the ones I have. All are near-microscopic worms that live in decaying organic matter. I feed them to my fry, along with baby brine shrimp. Mine are kept in cool-whip containers and every now and then I'll start a new batch, or culture. It's just instant oatmeal (Cooked and cooled), yeast and paprika. The new food is mixed together and I place a little scoop of worms from one of the already started cultures in the middle. They'll start eating up the mix and breed like crazy. Then I ignore them. They'll do their own thing for a long while, sitting on a shelf in a box with all the other containers, and all I have to do is scrape a few worms off the side of the container with a q-tip and add them to the fry tank. Very easy to keep and easy to feed. I only really bother when the old cultures get really runny, means they've destroyed the food source and need something new to eat. Though I have heard of cultures being forgotten and found years later, still alive.
Wow.. that was the long answer, wasn't it? Oh well, crash course on microworms!
I just went through my cultures and restarted two of them.. and now I'm bored again >.< Maybe a glass of wine will help me sleep.