Spades is a trick-taking card game that can be played with 3 players solo, 4 players solo, or 4 players with partners (2 teams of 2). A standard 52-card deck is dealt, then players bid the number of tricks they can take. The goal is to take as many tricks as were bid. When playing with partners, North/South is one team, West/East is the other, and teammates' bids and tricks are combined, so one player's underbid can compensate for his teammate's overbid.
This app allows you to configure number of players and teams, rules about nil bids and when spades can be lead. There are instructions included in the app, as well as a setting to make your robot opponents less aggressive or more aggressive.