Countermoves magazine doesn't seem to be alive anymore, but back issues are still online. Each issue featured one or more free wargames (some with public licenses, some copyrighted), as well as reviews, editorials, and strategy articles. The link above goes to a BGG entry for their generic wargames system, which was not CC licensed, but placed into the Public Domain, which is somehow entirely different from a legal standpoint, but IANAL.
This 'Party Game of the Year - 2008' uses Creative Commons licensed photos, so they had to CC license the game, too. With a few detective skills and a little perseverance, you can download and print the rules and pieces for free. Or you can play online. You can even buy a copy.
Pagat is the most complete, authoritative site on the web for information on card games. There are pages on traditional games with playing cards (most of which are now in the public domain) and commercial games, but check out the 'invented games' category for hundreds of games (including a few of my own), many of which have been published under Creative Commons or other public licenses. Some use their own printable cards, and some use playing cards. It's well worth a browse.