Since 2000, the Beneficial Brick Initiative by Portus Praha has helped raise $1000s for mentally handicapped people in and around Prague.
If interested and you happen to stumble upon the street stall, you are asked to donate a small amount of change and paint a brick with anything you like, before adding it to the giant 'jenga-like' wall.
The proceeds go towards the construction of a new building for Portus Praha and the bricks will be incorporated on site.
More images here. Image courtesy of Kelly Price.