Hitman: Who am I killing?

Dog: Ever heard of a guy named Pavlov?

Hitman: Rings a bell.

Dog: *narrows eyes* That's right.

@soundclamp

After a long day at the lab, Pavlov goes down to the local pub for a beer. He gets one, sits down at a table near the door, and starts unwinding.

After five, ten minutes the next customer comes in. That rings the little bell attached to the front door, and Pavlov jumps up and runs out of the bar, yelling "My God, I forgot to feed the dogs!".

@soundclamp

(Gotta give all the credit to a Reddit "what's the nerdiest joke you know?" thread, where I got this from.)

@jztusk Think this joke has been around longer than Reddit haha.