Roma pass

They figured out that little trick long ago. :-) Sadly, the free entrance is for the first two sites visited - no exceptions. That said, you will still get a discount at the Colosseum. The bad news is you won't be able to skip the line. There's more excellent info here: http://tinyurl.com/RonInRomePassInfo Use Ron's excellent info to crunch the numbers and determine whether you would actually save money buying the pass under your scenario, or not. He lays out one scenario where it's cheaper NOT to buy the pass. It has to do with whether you'll be using it for public transportation as well.

Michael, I understand your explanation, except for the part about not being able to skip the line at the Colosseum. Are you saying that you only get to skip the line with a Roma Pass if you are using it as one of your free entrances? Thanks for the clarification.

The best way to do this would be to go to the palatine hill first on Sunday, scan your ticket to get the free entry and then continue on your Sunday as planned but switching the order and doing the Borghese gallery before the National Museum. By doing this you will still get your free entry to the colosseum and forum as you are given two consecutive days to see the three sites and still having it count as one site. On Monday you can then return to the colosseum and forum and enter them for free and bypass the lines. Donna

The long lines at the Colosseum are to buy tickets. If you have already used your 2 free entrances, even though you would get a discount, you would need to wait in line to buy a ticket. However, if your schedule isn't changeable, you could try and get around the problem by buying your Colosseum ticket at the much less-crowded Palentine Hill location, or possibly the Roman Forum.

Great answers everyone! Thanks for your advice. We're staying right near the Colosseum, so it'd work easily to scan the ticket, and then just go the next day. Perfect!
Thanks again!