Rimshot! Well-played.
One that relies almost entirely on the acting to sell it (and doesn't look so funny on paper), is in "Green, Green Glow" when Lois and Clark are at his parents' house, and Martha mentions showing Lois to her room, unless .... and she trails off to let the implication hang in the air that Lois and Clark might be sharing a room while they stay there. As it sinks in for the two of them, Lois looks mortified and falls all over herself to protest, and Clark looks like he wants to sink through a hole in the floor, and it's just really funny.
