My most fun safety announcement was on Alaska Air when the flight steward came on an said something like "This is a very exciting flight, as it's the very first flight for our two pilots." (Everyone starts getting nervous at this point.) "Captain John and Captain Jane, please stand up and wave to your passengers" at which point two (unaccompanied, perhaps) kids stand up with huge grins and wave to the other passengers.

It was a good way to get the attention of everyone before we could all go back to ignoring the rest of the safety instructions.