Improv Game - I Am A Tree:

I Am A Tree:
One actor goes out on stage and says "I am a tree" taking a position as a tree, a second actor goes out and adds to the picture they are painting, and a third person goes out and finishes it. Then the person who was first picks one of the two and leaves the stage, leaving the leftover actor on stage as the start of a new picture.

Example:
Actor 1: I am a tree
Actor 2: I am a leaf on the tree
Actor 3: I am the grass under the tree
Actor 1: I’ll take the grass
1 and 3 leave
Actor 2: I am a leaf
Actor 4: I am a panda bear
Actor 5: I am a zookeeper
Etc…

However, as you play this game, it can become an amazing training tool at getting the cast to learn the kinds of stories each other like to tell. If instead of just painting a picture on stage, the objects you go in as can raise the stakes for the story and connect together with themes. As a result, "I am a tree" can become a great training tool for ensemble and comedy.

Example:
Actor 1: I am a tree
Actor 2: I am a spotted owl
Actor 3: and I am the impending doom from the "clean air act"
Actor 1: I’ll take the spotted owl
1 and 2 leave
Actor 3: I am the "clean air act"
Actor 4: I am a brighter better tomorrow
Actor 5: and I am the fog of un-reality
Etc…

That was a bit of a political example, but maybe that’s what one group loves doing stories about. My group usually ends up making fun of my love life, but I think that’s a good sign. Good-natured ribbing is usually a sign that people like playing together.