If you are a Reddit reader, you might like the Reddit Unity lens. Theres no PPA to install it like the other lenses I wrote about. However, Webupd8 has created a deb file to install this lens. You can download it here.
Once installed through the Ubuntu Software Center, log out or restart the computer for it to appear in the launcher.
Webupd8 mentions the Unity Reddit Lens doesn’t have a GUI to configure it. To add categories, you need to edit the /usr/lib/unity-place-reddit/unity-reddit-daemon file to replace/add categories.