I found this video on YouTube showing a working Stug G at Tankfest (Bovington). I've not seen a moving example before, and given my current painting project I found this quite interesting to watch.
"The StuG was an assault gun based on the chassis of the panzer 3. This example was restored by the Sd.Kfz foundation, it had sat on the bed of the black sea for 60 years after its transport ship was torpedoed by a Russian submarine. Two were raised a few years ago but the other one has not been restored yet."