Marcolm Gladwell's Tipping Point, one of the first popular books to address the role of hubs and connectors in the society. 

(from http://www.gladwell.com/books.html)

 The Kevin Bacon game requires connecting every actor to Bacon via the movies in which they played together. For example, Mike Myers is two links away from Bacon, as he played with Robert Wagner, who in turn played with Bacon.

Six Degrees of Kevin Bacon Game

(from http://www.endlessgames.com/games/games1.html)

The list of the ten most connected actors in Hollywood. Where is Bacon?

see pg. 62 in Linked....

Mel Blanc
The famous voice actor, that appears in most (759) movies. He lended his voice to such characters as Bugs Bunny or Woody Woodpecker.
(from http://povonline.com/COL133.htm)

The actor with the second most movies (692)... the porno start Tom Byron,
the 1999 Male Performer of the Year.

(from http://www.adultvideonews.com/archives/199903/bone/pix/03_by18_1.jpg)

Hubs everywhere,
Theodore Roosevelt, on of the biggest social hubs of his time, with over 22,000 acquitances.

(from http://www.cnn.com/SPECIALS/1999/panama. canal/stories/history/link.theodore.roosevelt.jpg)

p53, a tumor suppressor molecule, one of the hubs of the cell's regulatory network.

(from http://www.bio.umass.edu/immunology/p53.gif)

Rod Steiger, the biggest hub of Hollywood.

(from http://www.pdn-pix.com/legends/legends6/images/regular/rod_steiger.jpg)

Spider Man, who appears in over 1600 comic books is one of the hubs of the Marvel Universe. See, e.g. http://xxx.lanl.gov/abs/cond-mat/0202174.

(from http://www.to2.com/desar/pagflex.nsf/a4c41cd2d17ebbad8625688c0025e 0b9/328cc5c0852be8cf86256a6100607bce/$FILE/1%20Spider-Man.jpg)