10 stitch Blanket - it spirals till you run out of yarn. And you only need a pair of little double-pointed needles to do a whole blanket. None of the tedious pick-up-stitches across a whole long seam, as you have to with most "log cabin" patterns.
Fun math activity for learning doubles. Directions: Roll the die and double the number you rolled. Look for that number on your board. Cover it with a chip. The first person to get five in a row is the winner.