I've always been facinated with Fair Isle knitting, where different colors are switched in and out of a project, often with facinating results. Through... well, I wouldn't call it stubborness, but for some reason or another, I've never actually learned to knit. And I really, really wanted to do this Fair Isle thing.
So I learned about Tapestry Crocheting! I used THESE INSTRUCTIONS. The website has some videos that I'm sure are helpful but that I haven't watched.
I first started with a little iPod case, but I did it in the round with a complicated knitting grid and it didn't really turn out.
What you see in the top picture is a (rather poor) second attempt. I followed a knitting grid for a Fair Isle bag with a Gryffindor design on it. Crocheting, apparenlty, is much larger than knitting. If I were to finish this, it would be a banner instead of a bag. :P
The nice thing about tapestry crochet is that switching yarns is easy (provided you twist before you yo!) and it is two sided.