Who: Chipotle Mexican Grill
What: Customers will get free chips and guacamole if they can spot five differences in the three photos shown by playing the game Guac Hunter.
Under a timer, you'll have to click on the differences between the two photos and see if you can beat the clock. The prize, free guac and tortilla chips.
The sucky thing is the images rotate so you can't just quit and try again with the same two images. Still, if you can stick it through, you'll get yourself a free snack.
Where: All participating Chipotle locations.