Using a small wood fire, you can heat a beverage or pot of soup and, at the same time, charge a cell phone, light, or other small USB device. It's environmentally friendly, burning fuel more efficiently than an open fire, producing less smoke and CO2 emissions, and creating electricity. Unlike a portable solar charger, you can charge your devices at any time of the day or night.
It's a little pricey, but it will pay for itself over time. That time depends on the local price of electricity, but in India it is estimated to take about two years to pay for itself.
Available for $129 + shipping from - BioLite Stove (original designers) or The Roosevelts.
Larger home stoves are also available, but only in large quantities.