Mix a little tech wizardry in with a some hardcore nostalgia, and what you get is a potentially fantastic product from Retrozone that allows for downloadable content for an NES game.
The geniuses at Retrozone have dedicated their lives to keeping the retro gaming community fed with new innovations for old systems. And now they're offering NES fans the DLC-enabled game "Glider" to play. While "Glider" appears to be based off of an old Mac game, it's the first game to offer the ability to download new content for the game from the Retrozone website.
From the official website:
In the most advanced homebrew yet you control the paper airplane in search of a way out of the 60 room house. Fly over floor vents to get lift or use fans for a speed boost. This house wasn't build very well so you will have to avoid water leaks, arching outlets, paper shredders, and other dangers. Shoot down fast moving enemy planes with rubber bands for more points! When your paper isn't in danger, collect bonus items. Use the three saved game slots to continue later when The House beats you. The backup battery in the cart is socketed so it can easily be replaced with no soldering.
The Glider cart is flashable which means you can replace the built in house with brand new ones. Once you beat The House get a new set of rooms from www.retrousb.com and use a USB CopyNES.
While it may not be the most streamlined system, it is definitely an innovation that I never thought would see the light of day.