I found directions on the craftster forums for turning an old shirt into yoga pants. Most tutorials for this type of recon have you cutting the tshirt design down the middle. Who wants a design that is split down the middle? What fun is that? That's why this particular tutorial is especially brilliant.
Anyhow here are my new pants made from a Geek Squad tshirt that was too small for Mrblocko and too big for me. I'm pretty happy with how they turned out. They will be perfect if and when spring ever decides to arrive.
If I ever make another pair of these pants I'll cut them down so they are short length. I'm pretty sure these pants are supposed to fall just below the knee, but I'm short so they are more like pedal pushers.
Go here for the tutorial.