Fischertechnik is fantastic, but I guess mostly unknown in the US?

The tolerances are far worse than with Lego, but there are many more possibilities to build workng machines.

I'm just reading a book about technic history with Fischertechnik, where all kinds of differentials, steering mechanisms, planetariums (yes, with several planets, ecliptic, and so on) and even several types of mechanical clocks are built.