Any ideas of what to do while working through the holidays?

I've used up my vacation time and like many, will be working through the holiday season.  I usually spend my time calling on prospective clients or updating current clients.  So I find myself making a list of things I can do in the office, by myself, that will help our company move forward and not bore me to sleep.  Perhaps there are online courses?  Books to read?  I need to be careful that what I am doing isn't just about making me smarter, it's about my learning for the sake of making the company stronger.  With that... I ask you for your suggestions of something meaningful I can do over 3 - 4 weeks?  Maybe there is a course you know of?  Books to read?  Make a plan for new calls every day in 2010?

Maybe attend Harvard (yes... the real one) extension school online?  Work towards a masters degree?  Doubtful there is a course during holiday break but you never know.

http://www.extension.harvard.edu/management/default.jsp

Any ideas as to what I could do??