Another idea I found on Pinterest:
These painting were done on mini canvases and are too freaking adorable for words.
The one on the left is my Autumn Dotty Tree and the one on the right is my Dotty Apple Tree. (The leaves and apples were made using Q-Tips.)
This project doesn't take much time and looks really cute. Give it a try! Tip: if you're doing this with younger kids, you might want to get the background and tree base ready beforehand.