Passion fruit: Ripeness

I've just discovered that my folks' backyard (in the Shawnee National Forest) is covered, literally, in passiflora incarnata. The fruits are hanging like egg shaped Christamas ornaments. The problem is, they're all green!! When do these fruits ripen? What color do they get? How long does it usually take for them to ripen?

I answered you in vine forum :http://davesgarden.com/showthread/101054.html

(same link :)