I've been trying to think of things to make my best friend for her soon-to-be baby. I found a web site called www.make-baby-stuff.com that has a printable pattern for sewing baby pants.
Making pants is actually quite easy. You only need to cut out one piece for the pattern and with the right technique you can literally sew four seams and you have pants.
I decided to try and make some out of an old Patagonia t-shirt of my husband's. I forgot to take a "before" photo, but here's the "after":
By using the hem of the t-shirt for the bottom of the pants, I didn't have to hem them up. I made sure to use a needle that's best for stretchy material and be sure to stretch the fabric a bit as you sew, that way the seams won't bust when you stretch the pants later on. I added a ruffle made from the hem of the sleeves. I'm happy about this first try! I think I'll go to the thrift store right now and find some good T-shirts to cut up.