How do you ripen an avocado?
If your avocado is rock hard when you bring it home, put it in a paper bag and let it sit out on your counter for 2-5 days. To speed ripening even more, add a ripe banana to the bag. The banana gives off additional ethylene, which is fruit's natural ripening gas.
Once your avocado is ripe, see Superfood: Avocados for some great recipes.