On both sides of America there seems to be a move to alter the generic billboard advertising we are presented with.. Here are some links to projects on both sides of the States.

Walead Beshty: Passages part of the LAXART billboard take over in LA.  Check out their site for all the works on display: http://www.laxart.org

Staying on the West Coast and still in LA there seems to be so many billboards they just keep them coming.

The How Many Billboards: Art In Stead project brought together 21 artists and commissioned peices around LA.
Click here for the details: http://www.howmanybillboards.org/

On the East Coast things are done a little differently, without as much permission more on a guerilla style of take over of the billboards, With teams of artists and also people white washing billboards in an attempt to deliver a new look to the streets and their messages. 


Finally check out the Wooster collective which seems to be updated with those altering, commondearing and using billboards and advertising around the world, worth a look some great interventions.

Wooster Collective