I was going to post a Catholic Encyclopedia article on the subject, before I realized that the day didn't exist when it was written. Instead, all I have is the about.com article, which ties in nicely with the special on metrospirituality.

The Feast of Christ the King was created by Pope Pius XI in 1925. He created it to fix the way people were living like Jesus Christ didn't exist. The feast proclaims how Jesus Christ is royalty above people, communties, nations, and governments.

The feast establishes the titles for Christ's royalty over men: 1) Christ is God and holds high power over everything; 2) Christ is our Redeemer, He made us His by His blood and now we belong to Him; 3) Christ is Head of the Church, 4) God bestowed upon Christ the nations of the world as his special possession and dominion.

We also learn that Christ's kingdom is for everybody who wants to be with Him, and it's endless. Most importantly, Christ's kingdom is not this world.

Prior to the Roman calendar reform in 1969, this feast was celebrated on the last Sunday of October.