A neutron walks into a bar and asks how much for a drink.

This classic zinger gets its power from a clever pun. The punchline, referencing "no charge," works on two levels. In the world of the bar, it simply means the drink is free. But the real joke is a nod to a basic scientific fact, which is where the geeky fun begins.

For anyone whose high school science class is a distant memory, a neutron is a subatomic particle. Alongside its positively charged proton and negatively charged electron buddies, the neutron is defined by its neutral electrical state—it has zero charge. The joke cleverly drops this piece of physics into the most classic of all joke setups, the "walks into a bar" scenario.

By merging the mundane world of a tavern with the quantum world of physics, the joke delivers a satisfyingly nerdy punchline. It's the kind of gag that rewards you with a little jolt of intellectual satisfaction, making it a favorite among science buffs and pun lovers alike.