Gamma hedging is a way to hedge delta variations.

2012 Crude Oil Futures and Options Expiration Calendar

Theta θ represents Time decay in the Black & Scholes model, and is the first derivative of an option price with respect to the time.

Volatility Arbitrage, sometimes called Volatility Bets, is a alternative way to manage money using markets and derivatives.

Binary Options can be priced using Black & Scholes model.

Implied volatility derived using standard models isn't the same neither for every strike of a particular maturity. nor for different maturities.