I finally found some mung beans at the grocery store. I was sure I had seen them before, but they haven't had any in stock for awhile now.
I bought a tiny seed packet with instructions in the spring for a ridiculous $2.99. Not enough beans in there for my hoard! But at least I got to look at them. They're sold here as Moong beans in the grocery, which is why I couldn't find them to begin with. Hmmm. At any rate, now I have my first batch soaking on the counter. Hopefully they'll be ready for a nice stir fry this weekend.
Here's a simple set of instructions that are pretty much the same as my seed packet. The seed packet says to rinse them twice a day, and that it takes 7 days to sprout them. We'll see how it goes.