is there a way to search for movies based on the MPAA film ratings? G, PG, PG13, R etc? it seems like there is the ability to search for everything else, but I don't see a way to search for a particular rating. Seems like a no-brainer so I was a little surprised by this.
The Advanced Title Search includes a US Certificates section that allows you to check the codes you want to include.
You can get to the Advanced Title search by selecting Advanced Search in the second part of the Search bar at the top of almost every IMDb page (it normally shows All), then click on the Advanced Title Search text link.