Unfortunately, most pears sold at food markets are rock hard. But, with a little care, ripe pears can be yours in just a few days.
Whole Foods, which always runs sales on in-season fruits and vegetables, was recently offering organic pears (several varieties) for $1.69, down from the usual $2.49. The pears were far from ripe, but I bought six Bartletts to take advantage of the great price.
To ripen pears, just let them sit at room temperature until they start to soften at the neck, just below the stem. Putting them in a closed paper bag speeds up the maturing process, as ethylene gas produced by the pears (for ripening) gets trapped in the bag. I put mine in a bag and they went from concrete to perfectly ripe (and delicious) in about four days.
Once the pears are ripe, keep them in the refrigerator in an open plastic bag.