Two scientists walk into a bar, one says "I'll have some H20." The second one says "I'll have some H20, too." The second scientist dies shortly after.
I got two: The past, the present, and the future walked into a bar. It was tense. Schrödinger's cat walks into a bar and doesn't.
Two antennas meet and fall in love with each other and got married. The ceremony wasn't great, but the reception was!