Much thanks to these posts from Ask Ubuntu and OMG! Ubuntu! where all this information originated.
First, install indicator-datetime from terminal:
~$ sudo apt-get install indicator-datetime indicator-applet-complete dconf-tools
You'll need dconf-tools to enable display of date and day on the indicator. It defaults to only showing you the time. If you're fine with that then just omit the dconf-tools packages. You won't be needing it.
After installation is complete, you'll need to restart your desktop session either by restarting, or a quick log out and log back into your account. The indicator applet will then be available in your list of applets.
|List of GNOME applets|
Displaying day and date on indicator-datetime
To show the current date and day on the indicator,
Browse to /apps/indicators/datetime and enable the appropriate options.
That's it. Enjoy!