These paper logic goats look like a lot of fun and a great way to learn about logic gates, they’re not free, but only a couple bucks…

The central processing unit lies at the heart of every computer, a vast collection of microscopically small switches and logic-gates. Now, through the power of paper we bring you those same logic gates in goat form.
Presented here are the and-goat the or-goat and the not-goat The and-goat will nod his head only in you press the right button AND the left button. The or-goat nods his head if you press the left button OR the right button OR both buttons. The not-goat nods his head if you are NOT pressing the button.

Logic goats – [via] Link.