A while back someone showed me The Game of Set. It is most fun played with 3 or more people. You can find the rules online.

As an exercise I wrote a solitaire version in ZX Spectrum BASIC. Since then, I rewrote it in javascript/html5, javascript/xhtml, incr tcl, tcl/snit, and tcl/tcloo

Screen snapshot

Click here to play the browser version. This requires javascript. This has been tested in Firefox 11 and Internet Explorer 9. Download link

Click here to play the ZX Spectrum version. This requires Java.

Click here to download David Ashley's SDL set. This requires a C compiler. I did not write this version, but the output looks similar.