You may have missed it, but Pope John Paul II revived the granting of indulgences, and there are some "specials" now being offered. This article in a Canadian newspaper gives the story.
Catholic theologians explain the thinking behind indulgences like this:
Our souls suffer eternally when we sin, but we suffer temporally too, in that we hurt other people, and ourselves when we do evil.
If we repent, God forgives us, but we must still pay the price. Like a child who has stolen a candy bar and confesses to a parent, we are back in the good books, but we still must pay the shopkeeper. Similarly, we pay for the damage we do through sin, either on earth or in Purgatory.
In an indulgence, God allows the pope to draw on the goodness of the Jesus and the saints, paying the "shopkeeper" in our stead and letting us off the hook for the suffering.
I'm sorry -- who is the shopkeeper we're paying here? This is very interesting theology.