Spivak textbook  

Ahh, Michael Spivak's Calculus.  Simultaneously loved and hated by the students of Honors Calculus at the University of Chicago , this text is the first exposure to rigorous mathematics for these poor hapless souls. This text is referred to simply by the author's name, and really has more to do with real analysis than simple calculus. 

Michael Spivak is a reclusive mathematician who received his PhD from Princeton in 1964, and has since written a number of eccentric yet incredibly useful mathematics texts.  Between the yellow pig obsessions and spurious love for the number 17, Spivak has been writing books that beat calculus, proof techniques, and general good math habits into the heads of students, but in a nice way.  From here on out, Spivak will refer to the book itself, in the tradition of general U of C parlance.
Given the might of this textbook, you can see how it may warp minds and destroy souls.
Spivak has 5 sections, 30 chapters, and 670 pages.  Within those pages lie 667 soul-sucking problems, waiting to stump and confound ambitious mathematicians.  So how much time would you burn trying to complete this book?
A quick survey of fellow mathematicians more closely dealing with the text reveals that the average problem takes about an hour, with variance of a factor of two depending on the problem.  For simplicity's sake, we can say that each problem takes an hour each. That gives us about 27 days and 19 hours' worth of mathematics invigoration!  Oh joy!
Excuse me, I'm doing math!