From NASA: Apollo 11 Onboard Audio Highlights - These are not necessarily major milestones of the mission but are some of the more interesting and clearly recorded conversations the crew members had among themselves as the mission progressed.
After entering lunar orbit, the crew members are amazed at the lunar terrain as they fly 60 miles above the back side of the moon and await Earthrise and to resume communications with Mission Control.
As Neil Armstrong and Buzz Aldrin prepare to depart for the lunar surface in the lunar module Eagle, Mike Collins, in the command module Columbia, bids them farewell ... and tells them to take it easy.