This is a very simple prank that will be sure to get a lot of people frustrated all while you just sit back and laugh.

Step 1: Materials

Super glue
Coin of your choosing (Quarters and more valuable coins work best)
A smooth concrete floor or another strong smooth floor (it may damage the floor when removed if it is not concrete)

Step 2: Set Up

Go to the busiest spot you can find with the concrete floor (in front of vending machines or just after entry doors work the best).
Apply the glue to one side of your coin, and place it glue down on the concrete. Don't put too little, but make sure that you can't notice the glue.
Also it helps a lot, as with all prank set-ups, if there's no one around to witness.

Note: IT'S A MUST THAT THE COIN BE IN PLAIN SIGHT, DON'T TRY TO HIDE IT YOU WANT IT TO BE SEEN.

Step 3: Laugh

Now you get to laugh everytime you walk by and see someone bend over to pick up the coin only to find they don't stand a chance at getting it. Then you get to laugh even more when they turn red embarassed at their mistake in front of all their friends/co-workers.