With recent the recent wave of modded Xbox 360 console bans by Microsoft, loads of these boxes are going up on Craigslist.
According to a report on CNET, these modded come with a "slew of hit titles" if you want one despite the fact you can't log into Live with 'em. One listing promised a console with a 20Gb hard drive; 20 HD movies; and 13 games including Madden 2010, Modern Warfare 2, and NBA 2K10.
Apparently, these folks are selling the banned consoles to get money for a new one. No doubt. It also seems it's just the console and not the account that has been banned.
More through the link.