Scrabble GO features time-limited Arena Tournaments, where players compete with one another by playing quick, single-player game modes. Higher scores will move you up the Leaderboard to win big prizes.
You can access all live Tournaments from the Arena Tab at the bottom of the main lobby. Tournaments rotate through the different game modes and often include special and unique variations of those modes. Each Tournament is only available for a specific amount of time before cycling to the next Tournament.
Placing near the top in Tournaments by having the highest total score rewards you with League Trophies, which help you increase your ranking in Leagues (see: Leagues for more info).