Kind of a random question, but what are the blue wire-clamp-things in the image below called?

I see those everywhere, and I think they'd be awesome to have in a grab bag...
Kind of a random question, but what are the blue wire-clamp-things in the image below called?

I see those everywhere, and I think they'd be awesome to have in a grab bag...
Those are terminal blocks.
More specifically those look like eurostyle terminal blocks.
Those parts are a type of terminal connector - typically called a screw down or clamping terminal block. There are various types including PC-mount, 90 degree edge mount, and even surface mount. They also come with various numbers of positions (number of clamping wire terminals).
They make an excellent was of connecting larger gauge wire (such as for a motor, battery, speaker, etc) to a PCB board, but they introduce noise, so they are not well suited for sensitive lines such as data transmission.
Here are some at a site call all-electronics.com. They are relatively cheap.
2 Position PCB Terminal - Green
2 Position PCB Terminal - Blue