avr
The AVR is a line of microcontrollers offered by Atmel. These microcontrollers are impressive little chips, and a lot of hobby projects currently exist for them.
Currently I tinker around with what the AVRs have to offer. I find that programming in a "tight" environment like a microcontroller really helps one's understanding of various programming languages.
The projects listed here may not be strictly useful to people, but they should prove to be excellent examples