There are free games and there are free games. One of the best print and play games you can get for free is one of the worst: Cards Against Humanity.
Cards Against Humanity, the self-dubbed "party game for horrible people", is not a board game for everyone, but it is a board game for a lot of people (4 or more).
A lot of people have had a lot of fun with it, and you too can do so for free!
These days you can buy Cards Against Humanity for $39.95 (RRP), but the base set continues to be free under the Creative Commons license.
That means you can and may download the PDF, print it out, invent your own cards, and have a good time with your friends, just as long as you don't sell it without their permission.
So if you have a hankering to be horrible with your friends, download the PDF from here.