First, you gotta get a pumpkin or a turnip or something to carve up.

Then you do a complete lobotomy on it. Use a big spoon to get the brains outa the pumpkin. Fling them around the room to give it that "Hollow Weenie" decorative touch.

Then carve stuff like a face on the front of the now-empty skull-like thing.

Stick a candle inside to make the face show up at night. Hint: it works better if you light the candle.

Another hint: these instructions are invalid if you cook the thing first.