It's as old as the hills, but I'd never heard of the Three Sisters Garden until recently. The origin is unclear, but native cultures of North America are best known for their trio of corn, beans and squash.
Here's how it works: prepare the soil and build a mound 12 inches high and 20 inches in diameter. Plant four corn seeds in the center in a 5-inch square pattern (Native Americans placed them at the north, south, east and west corners). When the corn gets about 6 inches tall, plant six pole beans around the middle of the mound and four squashes around the edge. Later, thin the corn and beans to three plants and the squash to one plant.
The trio complements each other: corn provides support for the beans, which furnishes nitrogen for the corn. Squash leaves provide shade and help suppress weeds. The trio also provide good nutrition.
Simple, but effective.