I found this list on ASK.com
No.1 A man doesn't sleep with his friend's ex
This is the rule of all rules. No matter how hot she is or how much you always wanted to tap that, you, as a real man and keeper of the code, will not sleep with your friend’s ex-girlfriend, ex-wife or ex-anything. There’s no time frame until she’s available, this isn’t hunting season. Banging the ex of a buddy is like sticking a knife (or your penis) in his back. Be a man and fight the urge to hook up.
Penalty for breaking this man code: Your friend whose ex you’re doing? He’s now doing a woman close to you also. You call her mom.
No.2 A man has his friends' back
Fighting, tough times, sniping aliens on the Xbox, whatever it is, the second most important man code is to get your friend's back. No matter what it is (unless he says: “Hey, hide this from the cops”), you will be there for your buddy. If it’s a couple of fools who need correcting in the bar or if it’s listening to him sob about that skank you knew would leave him, you’re there for your bro.
Penalty for breaking this man code: You get labeled as “that guy” and your friends all avoid you, quickly realizing you’re a lame-ass bro.
No.3 A man gets the next round
Much like paying back your debt, a man gets the next round. If a group of guys is out and each is picking up the drinks, dig into your pockets and join in. Hiding in the bathroom when it’s your turn is not only lame, it’s pathetic. If the earlier rounds were foo-foo expensive drinks, just go with a round of domestic, healthy beer, you can’t go wrong.
Penalty for breaking this man code: You get called out at the bar because you secretly crave appletini’s over a good light beer. Every girl there will literally hear you grow a vagina.
No.4 A man doesn't cock block his friend
A foul deed and a rule that goes without saying, a man does not get in the way of his friend getting a piece. Inexcusable and downright evil, cock blocking is the quickest way to end a friendship and to get labeled Supreme Dick (and not in a good way). Don’t tell embarrassing stories, mention ex-girlfriends, start laying your own game, or do anything that will jeopardize a girl from seeing your boy in the best light possible (so he can see her in the dark).
Penalty for breaking this man code: A scarlet letter of your own, a giant red C for “Cockblocker.” And possibly an ass-whooping.
No.5 A man doesn't screw his friend on the job
In the workplace, man law is the real CEO and sees no glass ceilings. So while it may be tempting to end-run around your friend for a project or a scoop of insight in the office, you don’t do it if it’s at his expense. Job-blocking is just as bad as keeping your homey from scoring with a hottie. Be a friend on the job as much as you’re a friend outside.
Penalty for breaking this man code: All your sexual failures and frustrations end up on the office intranet and in memos to the hot new hires.
No.6 A man becomes a wingman when required
At the end of Top Gun,even Val “Iceman” Kilmer realized that Tom “Maverick” Cruise was the best wingman ever. Now it’s your turn. When you’re at the club or at a party and your friend needs you to take the ugly one so he has a shot at the hottie, you do it. Without question, you fall on the sword and are the wingman. Wingman duties can also extend to driving to the party, handling the valet and running interference from the girl’s man-hating friends.
Penalty for breaking this man code: You get grounded, shot down and denied takeoff. Everywhere you go, for an undetermined time, your male friends make sure you don’t get anywhere near getting laid.
No.7 A man buys his friend beers after he gets dumped/fired
The king’s horses and his men knew this code when Humpty Dumpty fell apart -- and you should know it too. When your friend loses his job or his girl, you’re there to ease his pains with alcohol. You get the rounds and you pick up the tab until he feels better or at least thinks he feels better.
Penalty for breaking this man code: Karma’s a bitch. Get ready to find your own sad ass in the unemployment line or spending your Friday night with Rosy Palm.
No.8 A man repays his debts
“Neither a borrower nor a lender be.” Sure, that sounded good when someone said it centuries ago, but in today’s economy, you may have to swallow your pride and ask for some financial help. Or, maybe you were short on cash or forgot your wallet (yeah right, you cheap ass). If your friend loans you cash or buys the first round, you pay him back. Work to get him his money, pick up lunch next time or get that next round of suds.
Penalty for breaking this man code: Working your debt off as your buddy’s man servant and house boy. And there’s that bachelor party donkey again.
No.9 A man doesn't say what happened at the bachelor party
Consider it a code of silence or an oath of nondisclosure. Whether it be strippers, midget tossing or stringing a donkey out on ecstasy, a man keeps these things to himself and especially away from the bride-to-be. Whatever happened at the party stays at the party.
Penalty for breaking this man code: That hyper-sexed donkey that’s tweaking in the bathroom is now in your bedroom waiting.
No.10 A man helps his friend move
It could be your buddy moving from his apartment to a house or out of his mom’s basement. Whatever the move, observe the man code that dictates you to help friends move. If you have a truck, it’s not even a question.
Penalty for breaking this man code: Think you’ll be able to ask for help moving when it’s your turn? Yeah right. Better get those furniture sliders and a good belt because your rule-breaking ass is on its own.
So true, you really learn who your friends are by things they do. Me and my buddy had a birthday party back in December, we invited some so called "friends", we booked our own room at 88 bar and dished out nearly 2000 RMB for drinks, food and cake. Not one of our friends brought us a gift or even bought either of us a beer. That just tells you who your friends are! I refuse to hang out with these people anymore, how hard is it to do something nice for your friend on his birthday??????