It would be rather hard to explain without pictures. Hmm... I'll try to find a tutorial or something.
Egh, I couldn't really find anything that would be suitable for a sweatshirt, although I did find plenty of ones that would work for t shirts (look
HERE for an extraordinarily easy one or
HERE for a harder one). I'll try to explain.
This comes out to be one of those tote bags with the straps that run up the outside of the bag. Like this, only less boring, and not as boxy (although, if you want a rectangular bottom, just tell me).
By the way, this is a modification of the tote bag from Generation T.
You will need:
A fairly large sweatshirt
An contrasting color t shirt that's more or less the same size as the sweatshirt
sharp scissors
tailor's chalk (not necessary, but it helps)
straight pins
needle and thread
1. Lay out your t shirt and cut two 5" tubes from the body of it. Cut through one side of each of the loops, making two 5" wide strips. Trim them so that they're both the same length and set both pieces aside.
2. Draw a 14" by 15" rectangle on what's left of the sweatshirt, using the tailor's chalk. Now, cut it out, going through both layers.
3. Pin the long sides of the two rectangles together, with the outsides facing in, and sew along the pinned edges with a whipstitch.
4. Take one of the strips you put aside in the first step and fold both of the long edges in to the middle a 1/2." Then fold the strip in half so that it is 2" wide and pin the long edges.
5. Pinch one end of the two strips together and thread them through the tube you made, going through the top, so that the ends you're holding end up at the bottom. Let the strips stick out an inch and position them 4" from the side seam. Pin them to the tube, going through all four layers.
6. Hold the to the other ends and pin them four inches in from the other seam with an inch sticking out, making sure not to twist the strips.
7. Sew across the bottom of the tube with a running backstitch, removing all pins as you go, except for pins holding the straps together.
8. Fold the top edge of the tube down 1" and sew it in place using a whipstitch. Turn the bag right side out.
9. Pin the straps to the outside of the tote. Make sure to pin through only one layer of the bag.
10. Sew along the edges of both strips using a running stitch, fastening them to the sides of the tote. Don't stop sewing when you reach the edge of the tote, sew along the handle edges too. I you want you can reinforce where the handles meet the top of the tote with a boxed cross-stitch on each intersection.
I had nothing to do, so I wrote a whole tutorial.