Microswitches And Contacts

Dome switch and Membrane switches

Also known as Rubber Domes, This kind of electrical contact is common for buttons in modern game pads, keyboards, television remotes and many other electronic devices.
Often the rubber dome comes per contact or comes in a larger unit or sheet as found in calculators and TV Remotes. Rubber domes may have a hard plastic plunger for the top portion of the button or uses a more of the same rubber as a protrusion for a push button plunger. The rubber dome covers over a contact point on a circuit board or a membrane with circuit paths, where the conductive material on the underside of the rubber dome comes in contact with

Leaf Spring Switch

Not to be confused with the automotive part of the same name. A Leaf spring switch or leaf switch makes electrical contact when the plunger or shaft of a push button or the actuator of a joystick pushes two thin pieces of metal together to create a electrical connection. These types of switches were very light as it requires very little force to engage or activate but due to the type of construction the switch wears out quickly.

Micro switch

The replacement for the leaf switch in arcades, and a alternative (and preferred) choice for the rubber dome in push buttons.
Usually 4 are found in per joystick, and 1 found per button. There are many styles and types of micro switches found.

Bibliography
: http://en.wikipedia.org/wiki/Keyboard_technology : partial reference