Not sure why I'd ever use this, but I just ran across the UNIX cal command and I found it pretty cool. You can use it to print out calendars from the command line of a UNIX/Linux command prompt.

There are a couple of useful usages:

cal -1 will print out the current month

cal -3 will print out the prev/current/next months

cal 2009 will print out a calendar for 2009 (change to any year you want)

cal 6 2009 will print out a calendar for June 2009 (change to any month and year)

Here's what the results for cal -3 look like:

Sample output from the cal command