Brain Game: For Roy
Just because you disagree with a war doesn't lessen the sacrifice made by the families of those who gave their lives during that war in service of their country. Having said that, this veteran will now kick that soapbox out from under him to bring you the mentalfloss.com Brain Game, Friday Free-for-all edition. Good luck!
Name a number that contains each
Roman numeral used exactly once.
My original answer was 1666, but Hal (see the first comment) reminded me that there are others, so I've incorporated them above.
Have a great weekend, everyone!