What can I say? I'm sure it must've been important to me when I was a little kid, but I don't remember it that well now. I remember the Captain, of course, and Mr. Green Jeans, and Mr. Moose and Bunny Rabbit. I especially remember the ping-pong balls always falling on the Captain. Really, it's a classic show and quite good and I wouldn't mind seeing some more of it.
Oh, I also remember the "Picture Pages" segment (IMDb; Wikipedia). Actually, while I probably vaguely remembered that from when I was a little kid, I now remember it best from like the mid-90's or so, when I would sometimes turn on Captain Kangaroo for nostalgic value. Until then, I probably didn't remember that the segment was part of this show.