Here's a classic from the GSI archives - Tom Pellegrino's "Characters In Your Leauge":

No good fantasy football league is without its fair share of characters. In going from league to league, you see that these people all exist in the same social experiment that is fantasy football. This is the fun part of the league. If you just drafted and played the games, that’s not fun. Leagues fail because of that. You need villains, heroes, and all of the characters in between. You need to make it personal among your friends, family, and co-workers, that’s what make fantasy football so great: the ability to take this great game to another level through these relationships. 

DARTH VADER
He’s the bad guy of the league. He’s won the championship before. He’s shrewd, good, tough, and he knows it. And everyone in the league hates him, and he knows that too. He causes you to not really work together, but to work against him. In order to have a good league, your league needs to have at least one Darth Vader. And if you are the league’s Darth Vader, feel good about it. It’s a great thing that you are part of the reason that the league is fun.

THE BLACK CAT
He’s the guy that seems to always have a team where four of his first six picks get hurt within the first weeks of the season… EVERY YEAR! He’s worse than the SI cover jinx, and the Madden curse combined. You want this person to draft people that are not on any other fantasy teams that you own; and it’s a bonus for him to draft people on teams that you hate. He’s the same guy that scavenges the waiver wire early and often to piece together a random team every week. Be fearful of this guy though, because just as you are thinking, “Yeah, but who has Matt Furrey on his team for his 82 yard, 2 TD game?” The answer: The Black Cat, the week he played you.

UNFROZEN CAVEMAN FANTASY PLAYER
If his team were the same five years ago, you could etch his name on the trophy now. But instead of the 2004 versions, he has the 2008 versions of Rudi Johnson, Isaac Bruce, Marvin Harrison, Bubba Franks, Mushin Muhammad, Warrick Dunn, and Alge Crumpler. But since he’s been frozen for five years, he hasn’t noticed that these guys are far from their prime form. He will defend his picks by saying, “If they are anything close to the way they were three years ago… LOOK OUT!”

BENEDICT ARNOLD
Have you seen the Best Buy commercial where the guy celebrates his team’s fantasy player scoring a touchdown against the NFL team he roots for? Well, that’s the guy. He’s the guy that cannot discern which is better, the “W” for his fantasy team, or the “W” for his NFL team. And if you have to think it about it, seek help. And you do not want to wind up sitting next to me at a Bengals game.

HOMER SIMPSON
He’s the opposite of Benedict Arnold. He’s the Bengals fan with Chad Johnson, Carson Palmer, Isaac Curtis, James Brooks, Rudi Johnson, Kenny Irons, Ickey Woods, Jim Breech, Doug Pelfrey, Boomer Esiason, Bob Trumpy, Anthony Munoz, Peter Warrick, and Shayne Graham on his team. And while it helps his rooting interest, it does not translate into a solid fantasy football strategy. He also might not necessarily show up to the draft prepared. “Well prepared” for him means borrowing a pen and a piece of paper. .
NOTE: In 2006, I was this guy in my home league. I went 7-7 during the year, taking Rudi Johnson in the first round and Chad Johnson in the second round. Trust me, you do NOT want to do this strategy, because you generally tend to have doubly bad days or doubly good days. And the doubly bad days are worse feeling than the doubly good days feel good.

CRAPPY TRADE MAN
He’s the guy that hopes that you didn’t notice that the guys he’s trying to trade you are broken or suck. He’s the guy that tries to get LaDainian Tomlinson for Randy McMichael, John Kasay, and the Browns defense. And then does not get why you do not want to make the deal. So then he “sweetens” the deal by throwing in Brady Quinn, but he’ll want you to add Vince Young. When he gets no taker, after offering the same deal to the rest of the league, he’ll drop him. That’s when you attack. No, that does not mean pick the person up, rather to the guy who dropped him say, “How did you drop the greatest kicker in NFL history?”

The antidote for him, is posting every ridiculous trade offer. Form a support group called, “People who’ve been offered Randy McMichael.” The fun part about this is that when you hang out with the guy start referring to McMichael as arguably the greatest tight end in NFL history, just to watch him tense up.

THE WALKING NO-TRADE CLAUSE
He’s the opposite of Crappy Trade Man. In a way, he’s even worse. He has a glaring need, he has someone you could really use, and you have someone he needs.

You make the offer. Nothing.
You even sweeten the deal. Nothing.
You make your absolute best possible offer. Nothing.
You bribe him. Nothing.
You buy him season tickets. Nothing.
You use calculus to prove that the deal will work for both sides. Nothing.
You bring in Mel Kiper, Jr. Dan Clasgens, John Madden, and Phil Simms to break the deal down. Nothing.
You try the Jedi mind trick. Nothing.
You threaten to hit him with a boat oar. Nothing.
You actually hit him with a boat oar. Nothing.

He thinks that you must be trading him crap and what he has must be very good. He’s so afraid to pull the trigger that he refuses to use the waiver wire to drop a player that sucks to get another player. Y’know? Just in case.

THE LAWYER
He’s the guy that needs constant clarifications on the rules. And he acts like this is all news to him. “So let me get this straight.”, he’ll say, “You can keep two players between one year and the next, right? What if I kept Peyton Manning, Chad Johnson, Two guys that aren’t even on my roster, The Edge, Marques Colston, and Antonio Gates? Would that work? Why not?” He also is the guy that tries to start six running backs, instead of using any wide receivers. He’s perpetually looking for an angle that just isn’t there.

THE ROOKIE
He likes football. He seems relatively intelligent. And he just wants to try out this crazy fantasy football thing that the young people seem to be talking about these days. So he drafts. And his team has every player on it that seem good (because they have TV ads, are talked about on TV or radio, and have lots of sound bites.) So his roster has players that are NFL good, but not really fantasy good (Ben Roethlisberger leaps to mind). He winds up going 4-10 in his first year, and hosting the league for the Super Bowl party. In every league, The Rookie always takes a beating, and then they get smart, and mix in well. But that first year…

THAT #@$&!%* GUY
I hate That #@$&!%* Guy. That #@$&!%* Guy is guy that is involved in every major controversy in the league. He’s the guy that thinks he got hosed on the draft order. He’s the guy that realizes he made a dumb trade, and wants it reversed; TWO WEEKS LATER. He’s the guy that thinks that league is specifically designed to destroy his team and rob him of his money. He thinks that every trade is an assault against his fantasy football empire. He thinks that the waiver system is football aristocracy and pure fascism. He’s the guy that calls you at 1:15pm on a Sunday while you are at a football game, out-of-town, or a family reunion out in the middle of nowhere and nowhere near a computer to inform you that the changes he wanted to make were not allowed because the games just started, but he SWEARS that he hasn’t watched a second of football (yet, they person he wants to start the game just caught a 90 yard bomb for a touchdown, but that’s just a huge co-inky-dink) AND DEMANDS THAT YOU DO SOMETHING ABOUT IT RIGHT NOW! He threatens to quit the league mid-season thus giving you the dreaded odd number of teams. You cringe when your caller ID says it’s him. He’s just That #@$&!%* Guy!!!!

DAY TRADER
Believe it or not, doubles as “The Whipped Guy”. He’s the guy that keeps hitting refresh on his computer screen to see if that four yard run from Reggie Bush got him anything. Mainly because he’s either A) beyond obsessed with fantasy football; or B) his significant other is thinking about other ways he could have spent $20-500 rather than on your stupid stat game. He’s like a stock market day trader, constantly seeing what a tiny occurrence did to his score instead of waiting for SportsCenter or looking around online at nine at night like the rest of us. He does this because if he has to report that he lost a fantasy football game, it will start another fight about money.

FLIPPER
Routinely last in the waiver wire priority order, The Flipper has two or three moves to make every week. His roster on the first week of the season looks vastly different than his roster at the end of the season. Usually he has about six of the same people.

THE COMMISH
He’s the guy that takes the phone calls. He sets up the rules, interprets the rules, and runs the league. And he deals with Flipper, Day Trader, The Rookie, The Lawyer, That #@$&!%* Guy, Crappy Trade Man, and Darth Vader all at the same time. And he’s the one drinking Pepto Bismol like they’re cold ones by Week Twelve.