My son has an Aquadoodle mat. It's basically a mess free kind of drawing mat. It uses water instead of markers and you draw on a thin fabric with colored fabric behind it (that's how the colors show up). It's fun because you draw on it, then when it dries you draw something else. Both kids like to play with it (my kids are 1 & 2).
Today, my two year old and I were learning letters. I would draw a letter randomly and he would tell me what it was. Eventually we were spelling words. He can now recognize the words "Mommy" and "Daddy", though I expect him to forget them by tomorrow. We'll see, he seems to be picking things up pretty quick now. He really enjoys saying the letters when they're written out.
Last part of my brag: He actually wrote a couple letters today as well :) Easy ones, of course, like "O" and "M".
Well, I'm off to go play some more with my little ones.