By John Stracke.
Fanorona is a traditional game from Madagascar, played on a 9x5 board:
As you can see, it's not just a rectangular grid like chess; the spaces are connected by lines. Pieces may move only along the lines. Notice that not all spaces which seem to be adjacent diagonally are actually connected. This turns out to be important for strategy: a piece can, in essence, hide from another piece, yet stay nearby.
More details are in the online help. You may also be interested in the Fanorona entries at Wikipedia and BoardGameGeek.
Fanorona is available in the the Google Play Store, either free or 99¢. The two versions have the same features; the paid version is basically a donation. If you have an Archos tablet, you can buy Fanorona in AppsLib, also for 99¢.