It's pretty rare that a portable solar-based device offers much more utility than impressing your friends, but PiSAT Solar's K-Light won't only make you the coolest kid on your block: it might actually prove useful the next time you take a hike or find yourself hanging out in a developing country.
K-Light is designed for up to 10 years of full daily use in such a scenario, and PiSAT is working on an adapter to let the lantern's battery also charge a cellphone.
That should be great for campers, but where the K-Light really "shines" (so to speak) is in places like Africa, where villagers without electricity often use makeshift kerosene lanterns for light at night.