3.11.2008
Some time ago Stefan Sagmeister showcased a funny guerrilla art project on TED. The artist sticks speech bubbles onto public advertisement and then the pedestrians fill the blank spots with their own thoughts.

In his talk he showed a lot of funny bubbles already however there is also a website which allows you to browse throw a lot of those bubbles and some of them are truly hilarious. Have a look.
Photo courtesy of Bubble Project