These are called ground cherries although they're kinda more like a tomato.
They have these adorable little paper sheaths around them kinda like a Chinese lantern. The sheath stays green until the fruit is ripe then turns paper like and brown. Sometimes they just fall to the ground and sometimes they stay on the plant and can be picked off. The shell protects the fruit when it falls to the ground and keeps it from going bad for a couple days. They have seeds like a tomato but aren't in the gelatin coating that has to be removed for saving. I got these as a plant from Seed Savers Exchange this year. I missed some of the fruit when it fell and it started a new plant. So I think they'll be easy to start next year inside before the last frost.
Above is the plant, it grows to about 4 feet wide so leave some room if you plan to grow these babies. They also grow close to the ground so they are aptly name "ground cherries."
Start saving seeds midway through the summer so you don't forget.