VW (Volkswagen), through the avant-garde advertising firm Crispin Porter + Bogusky, aims to counter RoadRage through advertisements that encourage viewers to commit to spontaneous acts of RoadJoy and register them on the website http://www.vwroadjoy.ca/. They offer 100 examples of this, including Guerilla Car Wash (getting some friends to wash an anonymous filthy car they see), Gridlock Bubble Brigade (stocking soap bubbles and wands to distribute to other drivers when there is a traffic jam), Jump Starting (carrying jumper cables to jump start a stranded motorist), Spot Donation (offering a choice parking spot to another motorist), The Wave (waving to someone who cuts you off rather than flipping them the bird — or elsewhere they suggest smiling at them or making a “peace sign”), Follow The Leader (telling someone who asks for directions to follow you there), or Rain Valeting (offering to bring a car around if it is raining). The website promises to feature RoadJoy activists in future commercials and also posts video or pictures of their acts.
For other ideas of spontaneous things you can do to build social capital, see 150 things you can do.
[Thanks to Lew Feldstein at New Hampshire Charitable Foundation for tipping me off to this.]