I worked at a startup that had a shared bathroom with a keypad on it. Somebody had the brilliant idea to tell the new guy the bathroom code was a 16 digit number. It worked because the only respected the last 4 digits to match the passcode. Everybody memorized the 16 digit code and made sure they entered it in when going to the bathroom when the new guy was around. The prank went on long enough that people wanted to see how long they could keep it going.
It was eventually spoiled when someone from the neighboring company witnessed the new guy entering the 16 digit code and pointed out the code was only 4 digits. As this was happening, it was witnessed by one of the architects and his cry of "NOOOOOOOOOOOO" could be heard throughout the floor.
Relatively harmless? Check.
Relatively undemeaning? Check.
Non-trivial amount of effort? Check.
Decent prank? Check.
Not that nice of a way to say "Welcome to the team"
This is not in fact a Startup Pranking website as I had thought.
-Fake techcruch article generator
-Automated fake VC calls
What I have qualms with though, is that you got my country flag wrong. You put a Zambian flag on Zimbabwe.
Also, why can't we just look at the Alexa stats for this?
Seeing the whole list and offering filtering options might make it a better tool for comparing social uptake and similar things.