This is an excellent series of bible studies for individuals and groups. This one contains a section for group leaders.
From the back:
"We despise our weaknesses; the apostle Paul delighted in his. We hate hardships and difficulties; Paul welcomed them as friends. We beg God to remove obstacles from our lives; Paul thanked God for such opportunities to experience his power. Throughout 2 Corinthians Paul turns many of our values upside down. He teaches us that in all circumstances we can rely on God's promise: "My grace is sufficient for you."