The problem with current wheelchairs? They're not versatile enough for developing countries' unpaved roads, steep hillsides and generally handicap unfriendly buildings. Enter the Leveraged Freedom Chair, a more powerful wheelchair controlled by levers that moves like a mountain bike.
The LFC is made entirely from bike parts and works similarly to a mountain bike. The wheelchair uses a lever system to maneuver with different grips offering different benefits—a high grip gives more torque, a low grip increases angular velocity—sorta like switching gears on a bike. Bonus points: any old bike shop will be able to repair it too.
The team behind the LFC actually built two models of the wheelchair, a version for developing countries and another for first-world countries. Buyers of the first-world model (better construction, lighter, etc) charitably pay for the developing countries' too. $3000 gets you the first-world LFC and gives three developing countries models away to those in need. [Core77]