Computer Science Unplugged

Computer Science Unplugged is a series of learning activities that reveals a little-known secret: Computer Science isn't really about computers at all!
CS Unplugged provides an extensive collection of free resources that teach principles of Computer Science such as binary numbers, algorithms and data compression through engaging games and puzzles that use cards, string, crayons and lots of running around.
CS Unplugged is suitable for people of all ages, from elementary school to seniors, and from many countries and backgrounds. Unplugged has been used around the world for over fifteen years, in classrooms, science centers, homes, and even for holiday events in a park!

And it's free!

You can download Unplugged activities as individual PDF files from their pages on this site, or download a teachers' version of the collection as a single file.

Lots more on this site.

But it's worth browsing this site. You'll find supplementary material for each activity: videos, links, plugged-in follow-up activities, photos, feedback, curiosities and more. We're also working on links to curricula, and new material is being added regularly. Printed versions of the Unplugged material are available for purchase, and proceeds from sales are put back into the project.
(By the way, we had noticed that Computer Science does seem to involve computers sometimes, and many of our exercises lead on to doing activities on computers, but the Unplugged approach is a great way to get students thinking about computing before they get distracted by the technical diversions that can inhibit thinking while at the computer.)