Ripen an Avocado quickly by storing it with a Banana
Store Avocados with Bananas to ripen faster
Avocado not as ripe as you thought? - keep them with your bananas! (or apples)
Ripe bananas, and apples, release a lot of ethylene, the hormone that triggers ripening in mature fruit, so placing one in a closed paper bag with your under-ripe avocados will speed up the process