When there's only one other person in the elevator, tap them on the shoulder and then pretend it wasn't you. Ask if you can push the button for other people, but push the wrong ones. Pretend you are a flight attendant and review emergency procedures and exits with the passengers. Hold the doors open and say you're waiting for your friend. After awhile, let the doors close and say, "Hi Greg. How's your day been?" Drop a pen and wait until someone reaches to help pick it up, then scream, "That's mine!" Push the buttons and pretend they give you a shock. Smile, and go back for more. When the doors close, announce to the others, "It's okay. Don't panic, they open up again!!" Ask, "Did you feel that?" Call the Psychic Hotline from your cell phone and ask if they know what floor you're on. Leave a box in the corner, and when someone gets on ask them if they hear something ticking. Swat at flies that don't exist. Bring a camera and take pictures of everyone in the elevator. Stand really close to someone, sniffing them occasionally. Call out, "group hug!", then enforce it. Move your desk in to the elevator and whenever someone gets on, ask if they have an appointment. Lay down a Twister mat and ask people if they'd like to play.