We've got quite a few things in the ground already (4" pea plants, lettuce, carrots, beets...) but the more tender plants we're waiting to put it until it's a bit warmer. But to give them a head start, Clay has started them indoors.
It's the simplest of setups, really. Just some cups in a tray (so you don't spill water on the counter) and a grow light (just a regular fluorescent light with a cool and warm bulb so you get the full spectrum). We have them sitting in the window, but we use the light too, otherwise they get too leggy. We covered them with pieces of wood until they sprouted, but would impatiently check several times a day to see if any green tips were peeking out.
It wasn't too many days until we were rewarded with cheerful, baby plants. Clay leans on the counter and gazes at his little seedlings all the time; I'm getting rather jealous. It really is a miraculous thing though. You notice more details about the whole exciting process when it's right there in front of you.
We've planted some herbs, zucchini, amaranth (what are we going to do with this? I don't know, but it looks cool in the garden), tomatoes, peppers and... I'm sure I'm missing some; he planted a ton. We used a lot of the seeds we got from Hometown Seeds as well as some we had saved from last season. I also got some pretty flowers and herbs that we're going to start inside so they're robust little seedlings by the time it's warm enough to plant them outside.