Passiflora affinis (Passion Flower) Passiflora incarnata (Maypop, Purple Passionflower) Click on the blue links for more information. I am not sure which species you have. And that is actually an edible fruit that's supposed to be very tasty but mine are a different species and have never produced any.
Passion flower. Love them. They will spread but are easy to pull up or mow down the ones you don`t want.
Maypop, or Passiflora incarnata is also a host plant for the Fritilliary butterfly. If you see little orange "worms" on your vine, leave them alone! They will become butterflies to enhance your garden.