How did the rise of organized sports and commercial amusements reflect and shape social divisions at the end of the century.It's somewhere in my...

Out of Many is the textbook that I
have used most often in my teaching US History at the college level.  In my opinion, the
text argues that the organized sports did more to bring people of different classes
together.  However it does talk about how the National League (baseball) was more for
middle class people (no alcohol sold, no games on Sunday, higher prices) than the
American Association.  So that is both reflecting and shaping social divisions.  Having
sports become a big deal also leaves lots of women out and deepens division between the
sexes. (End of Ch. 19 -- "National Pastimes")

The other
thing you should look at is "Gentility and the Middle Class."  Look at the part where it
talks about the middle class being able to buy toys for their kids (and bikes for
themselves).  This gave them a different experience than the lower classes
had.