Help beautify the mass transit system: post your ads on interior card displays inside buses, subways and commuter train cars. These displays typically fall into two main categories: side cards and end cards.

Side cards run the length of the bus or train. End cards are typically displayed (not surprisingly) at the ends of the train cars.

But why stop at interior cards? In major cities like New York and Chicago, "Brand Trains" are popular. This allows you to buy all of the vehicle's advertising space-inside and out. (Driver sold separately.)