The Science Friday show on NPR ran a contest--come up with a joke to follow the line, "A climate scientist and a climate change denier walk into a bar." These two are my favorites.
... The denier asks for whiskey but wants to see the bottle. The bartender shows him--it's 95 proof. The denier slams his fist on the bar and leaves. The bartender asks, "What's his problem?" The scientist answers, "Same old thing. You can show him the proof and he still won't buy it."
... The scientist says, "I'll have what ninety-nine percent of everyone else is having." The denier says, 'I'll have what the other ten percent are having."