A scan from my old Boy Scout Handbook from 1985. That I still have this page saved since then speaks to the depth of my interest in knighthood I suppose.
There are probably countless versions of the knighting ceremony, the simplest being a hard slap on the shoulder with the command "Be a knight".
John Boorman's "Excalibur" may have been fantastic and outlandish in many respects, but it's knighting ceremony was pretty standard: "In the name of God, Saint Michael, and Saint George, I make you a knight. Rise Sir ___"
The film "Dragonheart" touted a somewhat stodgy, idealized version called the Old Code: "A knight is sworn to valor, his heart knows only virtue, his blade defends the helpless, his might upholds the weak, his word speaks only truth, his wrath undoes the wicked."
Most recently Ridley Scott's "Kingdom of Heaven" delivers a well written version of the ceremony: "Be without fear in the face of your enemies. Be brave and upright, that God may love thee. Speak the truth always, even if it leads to your death. Safeguard the helpless and do no wrong; that is your oath. [Slap!] And that is so you remember it. Rise a knight."
Such virtues are mostly cast aside in popular culture nowadays. Most people view this stuff with doubt, dislike, and oddly enough, suspicion. Anyone who tries to behave this way clearly must have some ulterior motive, right?
I think Jeremy Irons sums up a realistic interpretation of an oath to be a good knight when he meets Orlando Bloom: "I pray God and Jerusalem that you can accomodate such a rarity as a perfect knight."