USB Digispark,Attiny85 based microcontroller development board,Similar to the Arduino line,only cheaper,smaller,a bit less powerful,With a whole host of shields to extend functionality,Ability to use the familiar Arduino IDE,A great way to jump into electronics,or perfect for Arduino of extreme size

Features
Support for the IDE 1.0+ (OSX/Win/Linux)
Power via USB or External Source - 5v or 7-35v (automatic selection)
On-board 500ma 5V Regulator
Built-in USB (and serial debugging)
6 I/O Pins (2 are used for USB only if your program actively communicates over USB, otherwise you can use all 6 even if you are programming via USB)
8k Flash Memory (about 6k after bootloader)
I2C and SPI (vis USI)
PWM on 3 pins (more possible with Software PWM)
ADC on 4 pins
Power LED and Test/Status LED (on Pin0)