Atanua is a real time logic simulator to help people learn some of the basics of electronics. Focusing primarily on logic, instead of power, this is a fantastic tool to learn with. They have done a fantastic job of making it easy to use as well as good looking. We can see this as being a should have piece of software for any hacker. There is a totally free version available as long as you aren’t using it commercially.

[Thanks ellisgl]