The list includes highly recognizable versions like Klondike (the one everybody knows from Microsoft Windows) and dozens of less well-known relatives like Spider, Pyramid, Golf, and Freecell.

And you can play all these solitaire games with Solitaired, a new solitaire compendium from Darshan Somashekar and Neal Taparia that also doubles as a teaching platform. Not bad for a freebie.

Released just under a year ago, Solitaired uses the spare real estate on a pack of cards to highlight important figures from world history.

You can choose from a number of different custom decks, many of them created in collaboration with august institutions like MIT's famous Lemelson program, the even more famous Encyclopedia Britannica, and NASA, whose fame extends into space itself.

These decks celebrate figures like the suffragists, the heroes of the civil rights movement, and history's greatest inventors, among other worthy subjects.

But Solitaired doesn't stop there. It also celebrates the graphic designers who are the unsung heroes of the playing card world. Included among the game's custom decks are classics like the Parrot deck and the iconic Jones Playing Card range.

Of course, Solitaired is above all a game, and it does solitaire as well as the best of them, with slick presentation, an intuitive interface, and enough solitaire variants to keep you entertained for life.

To take the classic Klondike as an example, not only does Solitaired give you the standard options of dealing one card or three, but it also lets you deal hands that are guaranteed to be solvable, or completely random. Plus, there's a dedicated game of the day where you can compete against your fellow solitaire fans for leaderboard glory.

Solitaired is free to download right now on the Google Play Store, the Microsoft Store, and the Amazon Appstore. There's an iOS version in the works, too.