I think all kids love to put on puppet shows, but when I was a kid my favorite thing was to act out television shows. We used to always pretend we were on TV. My kids made a theater that looked like an old box TV set, so they could put on a show and pretend to be on TV!
We used a large white foam board poster board, but this is the perfect project for recycling a large cardboard box. I cut out the "screen" opening. (I did this part for my kids, since I had to use sharp scissors and it was a little hard to cut for them.)
Then I let my kids draw on the details to make it look like a real TV. We searched for "old box set TV" online so they knew what box set TVs look like (since they live in a world where TV means a flat screen!). It was fun for them to see the old TV sets.
Next my five year old decided the theater should have a proper name, so instead of a TV brand he wrote "Kids TV Theater".
We cut the center cut-out in half so we could use it as the stand and taped each half to both sides of the back of the TV. That way the screen would stay up.
Place the stage on a table or on the floor and it's ready to go. My kids played with this for hours! We even played a fun game to see how creative they could be: one person was the "actor" and the other was out front with a pretend remote, and, anytime the person with the remote changed the channel, the actor had to change stories. Both kids really liked it.