Suicidal Teens Welcome
The sign in the window of the armed forces recruiting center (top) reads, "Suicidal Teens Welcome! Enlist Here!" The image is almost certainly fake. It would be a simple matter to paste the sign into the image, and then use Photoshop's opacity tool to blend the sign into the window, making it appear to be behind the glass.
Some have speculated that the hoaxer could have surreptitiously placed the sign in the window of the recruiting center and then quickly snapped the picture. This is possible but unlikely since it would be far easier to digitally alter the image then to stage the shot in real life.
The sign is a reference to an episode of The Simpsons (screenshot, bottom) in which a similar sign was shown in the window of an army recruiting center.
Links and References
• The Simpsons salute the lazy and uneducated. HotAir.com.