11. Tell them as they get on at the ground floor, "I hope you're not going up beyond the 10th floor. This elevator always gets stuck between the 10th and the 11th."
lol. Good ones. :)
I'd also add: Scream "Woooow!!" during the lift and then, when it stops, look around saying "What a ride, huh?!", then give people high-fives or something (then look a bit shocked when they don't return it).
Nice ones...Dang, that reminds me of an 80s tune.
10 is great.