SquareZ
To shake your rump is to be environmentally aware.
--David Byrne
Calling Ideas for July 14, 2012

This is:

National Nude Day
Woody Guthrie's Birthday
Called the father of American folk music (also the father of folk singer Arlo Guthrie), Woody wrote more than 1000 songs.

I have This Land is Your Land. Also, if you have a copy of Redwing, you also have Union Maid, a Guthrie song written to to the tune of Redwing. "Oh you can't scare me, I'm sticking to the union".
Dr. Spock's Book, Baby and Child Care, Published
This book is one of the biggest best-sellers of all time, and was probably influential for many of us baby boomers.

I guess any song with "baby" in it is fair game, but You Must Have Been a Beautiful Baby seems appropriate, or maybe Rockabye Your Baby (songs where "baby" is used to refer to an infant rather than a girlfriend).

July is:

National Hot Dog Month
National Ice Cream Month
Hitchhiking Month
Road songs
National July Belongs to Blueberries Month
Must be blueberry season; time to eat a lot of blueberries.

Can we say "Blueberry Hill"?

There's also a Nitty Gritty Dirt Band instrumental called "Bluesberry Hill" that a lot of callers are using for patter.