If you can listen to music, work your way through the 1001 Albums You Must Hear Before You Die. In a similar vein, pick out a few musical genres you are unfamiliar with, and look for a list of the essential albums in that genre. Then listen to a couple each day at work.
You could also listen along to the Coursera History of Rock course to learn about the history of popular music in the 20th century. As a fun side project, try to track down all the songs referenced in the course and make a giant playlist of them so you can hear the changing styles over time.
As mentioned elsewhere, podcasts are a popular way of passing the time. Many episodes of Hardcore History are long enough to take you through a good chunk of the work day. A couple of them will take you from morning coffee to lunch time or even almost to the end of the day to finish. Similarly, audiobooks during work is a good way to get around to some of those books you've been meaning to read for years.
Or maybe give Old Time Radio shows a try. There are some really fun shows that can keep you entertained for hours if you binge episodes.
These are all things I started doing shortly after landing a desk job. It really helped me overcome my depression and learn how to enjoy life even during the unpleasant and boring times. Through these efforts, I've discovered and learned a lot that has made life more fun and interesting.