So, I finally got my first programmable microcontroller. I've been meaning to start playing with one for a long time but never could justify the entry cost (for a newb-friendly one; yes, I know PIC's and bare ATmega's are really cheap) for just playing around until I found this one.
The company is PJRC, and they make two boards; the Teensy, and the Teensy++. The coolest things about these boards (for me, being new to the field) are that a) they can run both native C and Arduino code, b) they have native USB support (ie, no extra chip on the board to take up space like with the Arduinos), and last but definitely not least, c) the price. The Teensy without pins costs just $18, and the Teensy++ with pins (the one I got) only costs $27.