I made a few for some special people in my life just the other day, all various ages. One likes Batman, one likes Star Wars, one is just a little girl. On one side for the kid ones is white fabric that glows in the dark. Hope they think they are cool. I also made little cup rugs to match. One pic shows one side and second pic the other side.
Also, if you put mug rugs into the search box here you will find several posts and threads where folks made some or were in a swap. :-)