Phidgets are a set of "plug and play" building blocks, some low-cost electronic components that you can control from your personal computer via USB. They provide you with some extra input/output methods beyond the classic mouse + keyboard + screen.
As Harold Thimbleby mentioned in his book Press On, phidgets are a very nice way to get into hardware programming, as you may want to build real systems, not on screen or web browser simulations : phidgets are so-called because they are the physical equivalent of on-screen widgets (Windows Gadgets).
Phidgets = Physical + Widgets
(Widgets = Windows + Gadgets)
Where to find them ?...