I traced the pattern from my favorite existing pair of shorts and turned them into a pattern for these hot pants. It didn't take long, and with some careful cutting, I was able to preserve to logo (for the most part) and everything.
So go find an old t-shirt (or ask Randofo if you can buy a Simple Bots one like mine!) and get sewing!
Step 1: Cutting
As I said, I used a pair of my favorite shorts to make the pattern. I included a jpg of this pattern (because I don't know how to turn it into a pdf!). When you make your own pattern, don't forget to add seam allowance before cutting the fabric! I left 1" on all sides.
To preserve the main graphic, I needed to slit the shirt and add panels in to compensate for the legs. You can see from the patterns I uploaded and the pictures I took what I mean by this. I didn't actually create a center back seam, but left the top of the shirt as one piece.
So carefully cut a slit in the back of the shirt, and graft in two leg panels. I used a serger, but you can use a traditional sewing machine.
When sewing knits, be sure you're using an appropriate needle and a zigzag or stretch stitch so the threads won't break!