The Six Degrees of Sondheim

[KathyB]

I was hoping somebody else would run with this one so I wouldn't have to rely on my poor Googling skills.

Louis C.K. was a contestant on Celebrity Jeopardy! (** Unfortunately I can't find any proof of this other than my own memory, but I definitely do remember him being on.)
Cheech Marin was also a contestant on Celebrity Jeopardy (and Wikipedia backs me up on this one).
Marin voiced a character in The Lion King (movie), along with Matthew Broderick.
Broderick was in the original Broadway cast of The Producers, along with Cady Huffman.
Huffman was in the original Broadway cast of The Will Rogers Follies, which had lyrics by Betty Comden and Adoph Green.
Comden and Green played the Whitmans in Follies in Concert.



Johannes Gutenberg

[MartinG]

Johannes Gutenberg was born in Mainz, Germany, home town of...
Ferdy Mayne, who appeared in Revenge of the Pink Panther with...
Valerie Leon, who appeared in Up Pompeii! with...
Frankie Howerd, who starred in A Funny Thing Happened on the Way to the Forum.


Bertrand Russell

[Hester Jean]

Bertrand Russell is mentioned in Tom Stoppard's Jumpers
Diana Rigg played Dotty in Jumpers
And Diana Rigg was Phyllis in London's Follies

Ray Davies

[Leighton]

Ray Davies wrote the musical 80 Days, directed by Des McAnuff
McAnuff directed Forum for La Jolla 


Florence Foster-Jenkins

[Hester Jean]

Florence Foster-Jenkins was the subject of the musical Souvenir.

Souvenir started Judy Kaye.

Judy Kaye played Mrs. Lovett in the 2006 revival of Sweeney Todd.



Elizabeth Warren

[Chris L]

Elizabeth Warren won a Senate seat previously occupied by...
Ted Kennedy, who was the brother of...
John F. Kennedy, whose assassination was vividly documented in...
Assassins, by Stephen Sondheim.

John Legend

[MartinG]

John Legend appeared in Soul Men with...
Samuel L. Jackson, who appeared in Jungle Fever with...
Queen Latifah, who appeared in Cabaret with...
Catherine Zeta-Jones, who won a Tony award for playing Desirée in ALNM on Broadway.


John Coltrane

[Hester Jean]

John Coltrane was on Miles Davis' Kind of Blue album which was recorded at Columbia's 30th Street Studio as was the OBC of Company.

Antonio Vivaldi

[Bookman George]

Antonio Vivaldi's most famous work is a set of four violin concertos known as "The Four Seasons," which is also the title of a 1981 movie starring Len Cariou, who has a couple of Sondheim credits on his resume.

William Butler Yeats

[MartinG]

Yeats was an acquaintance (at the Abbey Theatre in Dublin and elsewhere) of...
George Bernard Shaw, who appears in The Frogs.


Beatrix Potter

[Leighton]

Beatrix Potter wrote Peter Rabbit
Peter Rabbit is being voiced by (my least favourite actor) James Corden in an upcoming film
Corden was in Into the Woods


David Dimbleby 

[MartinG]

David Dimbleby's daughter Kate appeared in a show about...
Peggy Lee, who recorded (or at least performed in cabaret) The Boy From..., Losing My Mind, Send In The Clowns, Do I Hear A Waltz and Together, Wherever We Go. Possibly more?



Alma Schindler

[Bookman George]

Alma Schindler was married to, among several others, Gustav Mahler, who is well-known to "The Ladies Who Lunch."



Doris Day

[KathyB]

One degree:

The seat was throwing my back out,
But there I was with a book,
When suddenly there's a blackout
And everywhere I look
Is a close-up of Doris Day,
Ninety minutes of Doris Day,
There was nothing to do but pray,
And how do we go? We fly!
Why?
How do we go? We fly!

Ty Cobb (either one of them, although I was thinking about the baseball player)

[Hester Jean]

Ty Cobb ( the baseball player,  I don't know another) played Baseball. 

There is a song about Baseball in Ragtime. 

Donna Migliaccio was Emma Goldman on Broadway. 

Mrs. Mig has played in many Sondheim shows.

W. Somerset Maugham