Then there are the fancy ones. A "double pole" switch can be used to reverse the flow of current, and so change the direction of an electric motor. A micro-switch is just that - a tiny switch that costs pennies to buy but pounds for a washing-machine engineer to replace. Many of these have three terminals. One is "in" and the other two are "out"; using one or other terminal means that the same switch can be used to either make or break the circuit.
Reed switches are special switches that respond to a magnet. Putting one of these in a circuit and bringing a magnet close to them will switch the current on or off. They are useful in models - a magnet on a wheel will work the switch every time the vehicle passes a reed switch. Reed switches are contained in a tough glass tube and need handling with care.
Burglar alarm pads - operated by the weight of the boot of a careless burglar - are featured in the curriculum for science and design and technology. "Tilt" and "tremble" switches that respond to movement are used to detonate bombs. You can make your own - but be careful you're not arrested for running a terrorist training school.