Wagering game having a ramping bonus feature

A method of conducting a wagering game on a gaming machine, the method comprising:

• receiving a wager from a player to play the wagering game, the wagering game having a basic game and a bonus game;
• randomly selecting a game outcome from a plurality of outcomes in response to the wager;
• enabling, in response to the wager being at least as large as a threshold amount, a hidden trigger for randomly triggering the bonus game, a probability of randomly triggering the bonus game via the hidden trigger being related to an amount of the wager;
• displaying the game outcome for the wagering game as symbols indicating a randomly selected outcome selected from a plurality of outcomes, wherein the plurality of outcomes includes at least one bonus-game-triggering outcome for triggering the bonus game;
• and
• activating the bonus game if the bonus-game-triggering event is achieved or if the hidden trigger randomly triggers the bonus game.

A gaming system for playing a wagering game having a basic game have a standard bonus game, comprising:

• at least one display;
• and
• a controller coupled to the display and programmed to
• initiate the wagering game in response to detection of a wager from a player, wherein a basic game of the wagering game displays symbols indicating a randomly selected outcome selected from a plurality of outcomes based on a first random-number generator event, the plurality of outcomes including at least one bonus-game-triggering outcome for triggering a bonus game;
• and
• enabling, in response to the wager being at least as large as a threshold amount, a hidden trigger to randomly trigger the bonus game based on a second random-number generator event, a probability of triggering the bonus game by the hidden trigger being related to an amount of the wager.

A method of playing a wagering game having a basic game and a bonus game that is triggered by an outcome in the basic game, comprising:

• receiving from a player a first wager amount, a second wager amount, or a third wager amount for playing the wagering game, the third wager amount being larger than the second wager amount, and the second wager amount being larger than the first wager amount;
• in response to the first wager amount being received, playing the basic game;
• in response to the second wager amount being received, playing the basic game and independently conducting a random selection with a hidden trigger that triggers a free play of the bonus game, the hidden trigger awarding the bonus game at a first probability;
• and
• in response to the third wager amount being received, playing the basic game and independently conducting the random selection with the hidden trigger, the hidden trigger awarding the bonus game at a second probability.