here's a little info about John Friend's "Eye of the Tiger" sequence, often called the Tigress Practice (a slightly shorter version).  This link takes you to Christina Sell's blog... she is a yoga teacher in Texas.  This 4-6hr practice is rockin!  At Elmhurst Yoga Shala, on the 1st Friday of each month (6pm-9:30pm) we practice a 3 1/2hr version. :) 

On a side note, my friend and yoga student, Jim Peterik (from the band Survivor) wrote the song Eye of the Tiger.  How Auspicious...  ;-)

http://christinasell.blogspot.com/2007/12/eye-of-tiger-back-story.html