US Patent 7611406 Gaming device having selectively activated extra reel

A gaming device including a plurality of primary reels with a plurality of symbols on each of the primary reels. At least one and preferably a plurality of the symbols on the primary reels are designated as activator symbols. An activator symbol is a symbol that, when generated on a primary reel, is adapted to cause the activation of at least one supplemental reel. The supplemental reel includes a plurality of supplemental symbols. After the primary reels spin to generate a plurality of symbols, the gaming device determines if an activator symbol is generated on the primary reels. If no activator symbol is generated on the primary reels, any award based on one of or a combination of the generated symbols is determined and any determined award is provided to the player. If an activator symbol is generated on the primary reels, the supplemental reel is activated and displayed to the player. The activated supplemental reel spins to generate a plurality of supplemental symbols. The gaming device determines if an award is associated with one of or a combination of the symbols generated from the primary reels and the supplemental symbols generated from the supplemental reel and provides any determined award to the player.