If you like hidden-camera style gags, I think this one is pretty inventive.
Once I was having lunch with my older sister and her friend, and when I was getting our coffee, a beautiful waitress walked past the waitress who was taking my payment, and kissed her on the neck. I don't know the back story of that, but as she passed me, I said "me too?". She hesitated for a second and said "nah, you're too tall".
A bit later, seated at the table with my sister and friend, she walks past and without warning bends down and kisses me on the neck. I look after her and she asked quietly "was that good?" I nodded. My table compadres didn't ask for an explanation, and I didn't give one. But it did liven up the day for sure.