My friend Yasmin told me about this website, where you can sign up for early or after-hours tours of the Vatican in small, exclusive groups. In their own words:

“If you’re really looking to impress, you could do no  better than book the exclusive tour of the Sistine Chapel by night, when  everyone else has been shepherded out of the awe-inspiring Cappella  Sistina. Savour the graceful architecture and contemplate Michelangelo’s  breathtaking ceiling in peace; a treat that very few get to  enjoy.

Or if you’re an early bird, how about skipping the queues  and signing up for the 8am tour, an hour before the Vatican museums usually  open? Numbers on these VIP tours are strictly limited and you will relish the  opportunity to have the Sistine Chapel almost exclusively to  yourself.

Italy With Us offers a number of other tours to help  you get under the skin of Rome. From evening walking tours to exploring the  ancient underground city, up to 12m below street level, its tour guides want  to share their passion and knowledge of the city with you.”