The other day, I watched my 4-year-old unroll the entire roll of toilet paper just to get the toilet paper roll. She then took the toilet paper roll, put it in the sink, soaked it, and laid it out to dry. Once it was dry, she painted it, covered it in tape, and used it as a telescope to find stars and planets.
Interesting games. Also, a combination of five and six would be interesting (for older children)