It does take awhile after the first 100 points if you do not want to register for a whole bunch of things. I've found the easiest is to watch for codes and listen to their internet radio. You can always turn your volume off and have it open in a window behind what you are working on. But you do need to check periodically - every 10 minutes reveals a code you need to type in to get your points.
The link is below. Happy earning!
This is the logo of the site:
Quite obviously, it is called instaGC.