Have you heard of a Magic Ball? It’s a ball of yarn that changes colors and textures as you work. It’s something offered by a number of artisan yarn makers… but it’s also something you can make yourself with your leftover yarn! Uses Russian join!
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.