For if/when you get married.

At the reception give every person a pair of nice dress socks tucked into a coffee mug that says, "I socked 'im twice and then I mugged 'im."

It is funny first for the obvious dumb joke, and then a day or two later when they realize you gave them a favor entirely disconnected from the event, and then a third time when they realize that without the socks, the mug doesn't even make any sense.

Also you could use that for most other events.