A few weeks ago, my daughter and I attended a sci-fi convention. The convention usually has some creative workshops, and we always enjoy them.
This time, we only did one, a shirt printing workshop. This is a very popular workshop at the convention, and the people running it are always updating and improving it.
The process is pretty cool, if a bit long (due to the images we chose). Since you first trace or draw your image on paper, it lowers the stress of ruining your shirt with a wrong move.
We ended up with a shirt for each of us, and are very happy with the result.