The Gift
American "hazing" in sports is a lot more documented than any other sport. The traditional rookie initiation usually involves the veterans trying to embarrass their new teammates. One common theme is to give the new player a gift that they must have around them at all times, like a Justin Bieber bag or this tricycle.
Unusual Haircuts
Staying in America, the second common rookie hazing thing are unusual or embarrassing haircuts. We have all kinds of ridiculous haircuts that you can see here or here (NSFW), but my personal favourite is reserved for Tim Tebow. Tebow is a devout Christian, so naturally the veterans on the Denver Broncos decided that this would be a suitable hazing ritual for him.
Drinks
Coming back to this side of the pond, a typically British story about Chris Ashton's initiation into the England squad. According to Ashton, the tradition in the England squad is for debutants to have one drink with all of the other members in the matchday squad. As Ashton put it "That’s one drink with each person and it’s whatever they want to have. After my debut I was battered."
The story goes that players are usually lulled into a a few beers, before the rum, gin and whiskey leads into the debutante being tricked into shots of vodka while the veteran has a shot of water.
Training Ground
It's a time honoured tradition that rookies have to do all sorts of tasks for the veterans, like these, but when you've to carry shoulder pads like such and can't see? That's gold.
Phone Pranks
Other times, teammates will give the rookie a fake number for a girl they think was checking him out. At least, that's what happened to Tony Bobbitt of the LA Lakers in the NBA. This joke comes from when Lucy Liu appeared courtside at a game. Bobbitt told teammates that he thought Liu had been checking him out during the game. His teammates came up with a fiendish plan to trick the new rookie. They instructed a ball boy to give a phone number to Bobbitt. Bobbitt was to believe that this number was Lucy Liu's when it was in fact the mastermind behind the plot Vlade Divac.
The whole team became involved. They read text messages that Bobbitt left for the fake number, before arranging a "date" for the pair. Of course, Liu was never to show. When teammates showed up to put the prank to rest, Bobbitt didn't believe them, insisting that she was coming.
Other Challenges
Sometimes, things go a little far and someone has to step in and stop what is going on. Much like Jonny Sexton's initiation into Racing Metro. Click the link for an in depth look, or listen to Jonny himself tell you about his close run in with a goldfish.
http://www.youtube.com/watch?v=Q4c39Q9Eyi4
NSFW Acts
You've already heard about the David Beckham initiation for Man United involving Clayton Blackmore, with United seeming to have several NSFW stories. The worst football NSFW story definitely comes from Stoke in the mid 1980's involving a glove that now has resulted in a legal case.
I'll let you check out the links, but needless to say, it's NSFW.
Punishments
When rookies are told to bring the veterans something, they better do it. This example above is proof of what can happen if the rookie doesn't bring in the required breakfast foods.
Just Pain
And the worst one of all is Matt Dawson's initiation when he played for the Barbarians. Needless to say, anthing involving a cactus,a bare ass and your best mate rarely goes well. Dawson subsequently refused to go on any more Barbarians tours. Read more here