In this tutorial I will show how to build a Digispark and how to flash the bootloader.
The Digispark is an ATtiny85 based microcontroller development board with integrated USB interface
It can be programmed using the Arduino IDE directly via USB.
It is a very cool and small all-in-one development board, and because it can act as a USB mouse or keyboard it is very popular for hacks and pranks.

Links:
Digispark Windows Drivers:
https://github.com/digistump/Digistum...
How to build Arduino ISP programmer (start at 2:04):
   • Program ATtiny85 directly via USB  

2 Board URL’s for the Arduino Board Manager:
(file—preferences—additional board URL)
Micronucleus : http://drazzy.com/package_drazzy.com_...
DigiSpark : http://digistump.com/package_digistum...