I'm looking for free chess playing software without strings attached.

A quick look shows lots of supposedly free offers, but you have to install their toolbar which feeds popups from their advertisers, or it is a 60-minute limited use program that you have to buy, or you have to give your email address so the spammers can attack, or... you get the idea.

Does anybody have any recommendations? I am an adequate player but certainly no expert, it doesn't have to be Grand Master equivalent by any means, just something with selectable skill levels to play a quick game once in a while.

tanstaafl.