Okay, here's the Wiki entry on Saturnalia:
...A number of scholars view this festival as the origin of later Christmas celebrations, or at least as contributing to them. Others point out that the Christian feast of Christmas on December 25 does not coincide with the date range of the Saturnalia, and that Christmas in any regard has not always been celebrated on December 25. The Catholic Encyclopedia states that church's view on the matter by saying that while midwinter pagan feasts such as Saturnalia may have helped influence the eventual choice to fix the date of Christmas, this does not mean that Christian Christmas traditions find their origin or inspiration there: "though the abundance of analogous midwinter festivals may indefinitely have helped the choice of the December date, the same instinct which set Natalis Invicti at the winter solstice will have sufficed, apart from deliberate adaptation or curious calculation, to set the Christian feast there too."
Just remember these three things:
1) Say "Io Saturnalia" a lot;
2) Find out which Roman Pagans are still around to answer back;