Carnival

Reading up on Lent, I find it interesting how man can institutionalize and commercialize holidays/events to the point where we lose site of the origin and meaning. Christmas, Easter, Fat Tuesday... if I weren't a believer, I would have no idea these had any connections with Christianity at all. What do christmas presents, the easter bunny or mardi gras have anything to do with Jesus Christ? How did fasting and giving up meat turn into a massive party and the giving away of beads?