One real world example ... turning internal interators into external iterators. See [link|http://jimweirich.umlcoop.net/articles/same_fringe/index.html|http://jimweirich.um...fringe/index.html] for details.
Another real world example ... programming web page navigation (supporting the use of the back button) in a linear manner. See Avi Bryant's work with Seaside (Smalltalk version -- [link|http://beta4.com/seaside2/|http://beta4.com/seaside2/]) and related work with Borges (Ruby version -- [link|http://segment7.net/ruby-code/borges/borges.html|http://segment7.net/...orges/borges.html]).
I've also written some stuff on Continuation Passing Style, tail recursion and call/cc at [link|http://onestepback.org/index.cgi/Tech/Programming/Kata|http://onestepback.o.../Programming/Kata], although this is probably much the same stuff that you are getting from your Scheme book.