The Digispark is an Attiny85-based microcontroller development board similar to the Arduino range, but cheaper, smaller and a little less powerful. With the possibility of using the Arduino IDE, the Digispark is an excellent way to get started in electronics, or perfect for when an Arduino is too big.

The Digispark is delivered fully assembled, except for the two included connectors which are easy to solder.

Here are the specifications:

Arduino 1.0+ IDE support (OSX/Win/Linux)
Power supply via USB or external source - 5v or 7-16v (12v or less recommended, automatic selection)
Integrated 150ma 5V controller
Built-in USB
6 I/O pins (2 are used for USB only if your program actively communicates via USB, otherwise you can use all 6 pins even if you program via USB)
8k flash memory (about 6k after the bootloader)
I2C and SPI (USI screws)
PWM on 3 pins (no more possible with PWM software)
ADC on 4 pins
Power LED and test and status LED