Logic (Shown in the Spirit of Nerdom)

F = f(A,B,C) = (A ⊕ B)C

as shown below:
And when it works, the LED lights up:
I'm glad that I'm not a digital hardware engineer, and you should be glad as well, seeing as this took me two hours to plan and build. In all fairness, it's my first logic circuit, but it is considered very elementary by digital guys. I call it spaghetti.

Here's what a 'hard' project looks like:
Now that's some crazy stuff.