To run upwards on an escalator going the opposite direction. In other words, running upwards against an escalator headed down. Typically, dropboxing is done on extended escalators such as those found in many large US cities, such as the ones providing access to the Washington, D.C. metro rail.
Jim and Tony were really sore after a late night out ended with the two dropboxing the Chinatown metro to impress Kathy and Diane.
n. software that is no longer sold or supported by the original publisher / developer, often found as free downloads on the internet because it cannot be obtained elsewhere. Not legal, but often seen as morally acceptable because the company that made it is no longer selling the title, nor releasing it as freeware, therefore abandonware is "keeping the gamealive", so to speak.
Doom II is not abandonware because idstill sells it, while The Incredible Machine is not sold, therefore is abandonware.