At GameColony.com you can play games of skill only -- play for free or play for $prizes!
According to the statutes of most states in the United States, gambling is defined as: "risking something of value upon the outcome of a contest of chance". (Also see No Gambling!) In games of skill (as opposed to games of chance), skill is a predominant factor -- winning is not a coin toss and not a 'gamble' anymore! So when you are playing games of skill (as opposed to games of chance) for $prizes, then, it has nothing to do with gambling per se -- a more skillful player has predominant chances to win and will win far more often.
The chance element of a 'gamble' is either missing or is insignificant in games of skill. When players compete in tournaments or games of skill for $prizes -- it is "competitive entertainment" rather than "gambling". The more skilled winner will eventually prevail and will win more matches, tournaments and $prizes.