Flipside's Mancala FS5 features the most popular version of Mancala, called Wari. (Mancala is a family of games, not a single game.) Although the oldest extant examples of Mancala-style games only date to the 7th century, I have no doubt at all that it's far older. Based on its continued ubiquity, in various forms, among contemporary primitive tribes, it seems likely that Mancala and similar "capture" games are one of the earliest stages in the development of the boardgame. Since these games were usually carved in the dirt and played with pebbles, ancient examples are simply less likely to have survived.
The game itself remains quite entertaining. There are 6 small depressions on each side (called "houses") and one large depression at either end (called "stores"). There are a fixed number of pips in two colors: enough to fill 6 houses per side with 3, 4, 5, or 6 pips each. (Four is the standard, but Mancala FS5 allows variable setups ranging from 3 - 6.) Players alternate "seeding" by taking all the pips in one cup and counting them out to the right, one pip per cup, including the stores. Pips that land in the stores are considered captured. If the last pip of your turn is seeded in an empty house, you capture all of the pips opposite that house. The goal is to capture the most pips. The game has some subtle strategies for seeding and capture, and repeated play reveals more depth than may be apparent at first.
Flipside's version of the game is my favorite, but it's not with problems. I like the board, mechanics, and feature set. There are variable setups, and strong 2-player support via pass-and-play, Wi-Fi, Bluetooth, online automatic matchmaking, and AIM. I don't do much of the multiplayer, and I certainly don't pay any attention to the rating system, but I understand that rated play has problems with scoring. These problems are mostly attributed to a scoring system which fails to account for twits who bail out of games they are about to lose. These incomplete games leave the remaining player forced to forfeit, which negatively impacts their rating.
The free version is also well-nigh crippled by an in-game advertising system which causes 5-10 second delays between games. Even the $2 version includes some ads, albeit not as aggressively. (No paid app should ever include ads. Period.)
These failings are unfortunate, since the design of the game is very good, and Mancala is an abstract strategy game that is worthy of rediscovery by western gamers.