Since it's been at least ten years, possibly twelve, I'm guessing the Statute of Limitiations [1] has kicked in and I'm free to discuss such matters now, although to be on the safe side, I won't mention my co-conspirators in this.
Anyway, over a decade ago, on March 31^st, some friends and I found some crime scene tape somewhere on the FAU (Florida Atlantic University) [2] campus. Realizing a good opportunity when it arrives, we took it upon ourselves to festoon the ground floor elevator in the Computer Science and Engineering Building [3] with said tape. We also took a roll of masking tape, and placed a body outline in said elevator, only with the hand sticking out of the door. One would have had to get off on the second floor to see the matching tape outline of the hand.
It was a sucess for as long as it lasted, as we did scare the cleaning crew, but alas, it was cleaned up fairly quicking the next morning, April 1^st.
I was reminded of that when I saw this elevator [4] and thought, man! That's much cooler than what we did!.
Although, that looks like it took some time to plan and execute.
[1] http://www.answers.com/topic/statute-of-limitations