I'm a native Floridian, so the odd, husk-covered tomato thing called a tomatillo is not foreign to me. They're not something I see every day though, so when I do, I definitely buy them, in large quantities.
You can use them for a lot of things. Cut them up and put them in salads, for example. I will sometimes put them in guacamole instead of diced tomato, which is fun because then it's all green (also handy since my boyfriend doesn't like tomatoes). They're brite and crisp and not really at all like the texture of a tomato.
The best use for them is salsa - not only is the salsa delicious, but you can also can it and have a taste of tomatillo throughout the year.
2 lb tomatillo, shucked
2-4 jalapeno or cayenne (or your pepper of choice), chopped
1 bunch cilantro, chopped
4 cloves garlic
2 limes, juiced
Salt and pepper to taste
Either on the stovetop or in an oven at 425ºF, char the tomatillos till their black on two sides. This is not a required step, but it helps to give a little softness to the flavors.
Chop the peppers and garlic coarsely. Use the seeds if you'd like a little extra spice. I like using red peppers, like cayenne, because it adds a little more visual dimension to the salsa.
Add all the ingredients to the blender or food processor. If you're using a blender, you may need to add a bit of water to make it all come together. However, there should be enough liquid from the cooked tomatillos.
When fully blended, you can serve. Or you can cook on medium high for about 20 minutes and then process for 15 minutes in a canner for storage. This makes about 3 pints.