As previously mentioned, Christmas brought my son a slotcar set that entertains me no end. I've continued to explore it and learned a few things.
1. The track doesn't have to be a closed circuit. The other day I built a long straightish track from the kids' room over to the opposite end of our apartment where my wife was watching TV. Then me & our daughter sent cars rattling over for the poor woman to turn and send back to us when we'd rotated the power supply.
2. The cars are mainly held on track by magnets on their under-sides, grabbing the conductors in the tracks. Two of the cars are of a useless make and keep de-railing all the time, because they have only one magnet each. The good cars have three. I tried gluing the magnet from one of the crappy cars onto the base plate of the other, but it still sucked. Oh, well.
[More blog entries about slotcars, toys, modding, children; bilbana, leksaker, barn, modda.]