What is the Best FREE Fantasy Football League?

I’m looking for a league that offers trades during the draft (ex. trading draft picks to another team in exchange for a player they just drafted). I don’t know if there is a league like that or not. Also, it would be tight if there was a keeper league that offered trading during drafts. If you don’t know of one, just list a fantasy league that you thought was kick ass and then leave a line or two explaining why you thought it was a good one. I’m trying to find one that is pretty realistic, as far as each fantasy team owner can almost feel like a real GM of an NFL football team. Thanks

I played in the league that NFL.com offered(the stats were provided by CBSsportsline.com) and have been for the past 3 years. I was the commissioner, but for some reason I still didn’t have any special options, other than kicking someone out of the league before the draft started. It kind of sucked.