A.,
Get a Crib Tent. That is what I did when my youngest started climbing out of his crib when he was about the same as your child. Not only was I frustrated by his crawling out when he should be going to sleep, I was worried about the idea of him waking up in the middle of the night and crawling out and getting hurt.
Many people will be against this I am sure. But the tent I purchased was a mesh pop up - completely see through that attached to the rail system of the crib. We made it fun for him - he got to "camp out" in his crib. He didn't fuss about it and I had peace of mind that when he was sleeping and I was sleeping he wasn't going to be able to get out of his bed.
Good Luck! My little crib climber now - at the age of 3 1/2 is the biggest dare devil of my three boys:) Just recently he "Surfed" down the stairs in a laundry basket, so you may have many years of adventure ahead!
T.