I'm pretty sure I've spoken about it before, or even shown off a finished one. But I had an idea, and it's turning into a very pretty one.
Just take the Bubbles Baby Blanket pattern and two colors of WW yarn. A dark and light yarn will work best for this. Now, using about a J or K hook (I'm using a 7mm bamboo hook) and your MC, crochet a chain the length you want your afghan to be. Just make sure that your stitch count is a multiple of three, plus two (This means crochet a ch with a multiple of three, then add two more chs at the end). Now, work across the chain like the instructions say, only change to your CC in the last stitch. Do this by making the last half of the sc with your CC. Now, leaving about four or five inches, cut MC and tie the two ends, along with the tail from your starting ch, together in an overhand knot and push it up close to your work. After this, just tie the MC and CC together when you change color.
That's it! Just swap colors on each row, and soon you'll see that you'll have a double-sided blanket. Your yarn ends become the top and bottom fringe rather than you having to work them all in. Normally, I don't like fringe, but I hate working yarn ends in even more, so this is me being lazy. But it looks good in the one I'm doing. I will post a pic when I'm done. I've only just started, but it still works up fast.