I was curious about Christmas Day games, so, from wikipedia ...
Christmas and Christmas Eve games
For more details on this topic, see National Football League Christmas games.
In recent years, the NFL has generally scheduled games on Christmas only if it falls on a day normally used for games (Thursday, Saturday, Sunday, Monday). If Christmas falls on a Sunday, as it did in 2005, most of the games will be played on the preceding day (with no games that night or the following afternoon in deference to the holiday), and then one or two games are scheduled for Christmas Night to be broadcast nationally. One game would be held over for the regular Monday night slot and one would already have been played on Thursday. Through the 2006 season, there have been 14 such Christmas contests.
The first NFL games actually played on December 25 came after the merger during the 1971 season. The first two games of the Divisional Playoff Round were held on Christmas Day. However, the second of the two contests played that day, the Miami Dolphins versus the Kansas City Chiefs, wound up being the longest game in NFL history.[18] Because of the length of this game, the league received numerous complaints, reportedly because it caused havoc with Christmas dinners around the nation. As a result, the NFL decided to not schedule any Christmas Day matches for the 17 years that followed.
The NFL continued to avoid Christmas even after it started to increase the regular season and the playoffs. The league expanded to a 16-game regular season and a 10-team playoff tournament in 1978, but it was not until 1982 that the regular season ended after Christmas, due to the player's strike. Finally, in 1989, the NFL tried another Christmas Day game, the Cincinnati Bengals at the Minnesota Vikings, but it was a 9 p.m. ET Monday Night Football contest, thereby avoiding interfering with family dinners. In the years since, the NFL has played an occasional late-afternoon or night game on the holiday; but there has not been a Christmas Day game starting earlier than 5 p.m. ET since 1971.
There have also been several games played on Christmas Eve over the years, the most famous of these being a Oakland Raiders-Baltimore Colts playoff contest in 1977 which culminated in a play immortalized as "Ghost to the Post". These games have typically been played during the afternoon out of deference to the holiday. If Christmas Day falls on a Sunday, then most of the weekend's NFL games will be on the afternoon of Christmas Eve, except for a few games held over for the Sunday and Monday TV packages.
In 2007, television contract obligations led to the league scheduling its first prime-time Christmas Eve game, when the Denver Broncos met the San Diego Chargers in San Diego on December 24, which happened to be a Monday. This game started at 5 P.M. local time (8 P.M. Eastern), and both teams were from the western United States.
Based upon current television contracts, the next Christmas game will take place during the 2009 NFL season. Whether it will be on Christmas Eve or Christmas Day has yet to be announced.