Remove the shower head and place a chicken bouillon cube in it, then put the head back on.

 661

1  

Put a "Please Use Other Door" sign on the entrance to your office building if it only has one entrance.

 1407

1  

Put tape over the optical sensor of someone's mouse.

 808

1  

Find a sleeping person, fill their hand with shaving cream and then tickle their nose.

 762

0  

Hide all of the desktop icons on someone's computer and replace the monitor's wallpaper with a screen-shot of their desktop.

 837

0