LEGO is great stuff. This weekend we built a fast train track in our living room. David is the engineer, Peter operates the trains. The art is to build it in such a way that the trains make real speed, but don't crash out of the track.
Over dinner I told the boys that I own a pet flee called Little Pete. I keep him in a little box in my wardrobe. This flee is so small you can barely see him, but he can do little saltos in the air. When I showed it to them, they were impressed. Then I acted that the flee suddenly jumped out of the box into Peter's shirt, and I had to catch him again. Peter said: "I felt him tickle me, dad."