There is no end to the modifications of bicycles. The most economically important alterations though are the many ways in which mobile resturants and stores are created from bike technology, or to be more exact trike technology. The three wheeler is very stable and easy to maneuver.
You can ride your store to the corner of the park and sell fruit and drinks. Note the cool awning.
You can haul a lot of stuff to your corner, including ice chests, burners, supplies and an umbrella.