We're fans of littleBits, the prototyping kits that make it easy for anyone to mess around with electronics. Now they're even better with the just-released Arduino at Heart module.
The Arduino at Heart module is a tiny, programmable littleBits module that you can connect to your other littleBits parts. Like other littleBits modules, it snaps into place and is incredibly easy to use. As you'd expect, you can upload your Arduino programs right to the module with a USB cable. If you already have some littleBits, the Arduino at Heart module alone will run you $US36, or you can grab the full kit for $US89.