“It’s especially fascinating to hear the behind-the-scenes stories of how these pioneers influenced each other. For example, Mary Tyler Moore talked about how Lucille Ball hid in the studio catwalk to watch rehearsals of the “Dick Van Dyke Show.” One day Lucy laughed so hard she blew her cover — and then came down to offer Mary life-changing advice.”
I never heard about this before, so I thought I'd share. This story is to be included as part of PBS's four-part "Pioneers of Television" documentary series in January...

http://www.pbs.org/aboutpbs/news/20070213_pbspioneers.html

Thanks to T-Greg for the link.

That was interesting, LOL. I can see Lucy doing that.

This special looks like it'll be fantastic!! I look forward to watching!!

Mary had that story about her in her book.