Are you and your girlfriend adrenaline junkies? If you think jumping out of a plane at 2,000 feet sounds like a great date, popping the question under extreme circumstances is the way to go.
Present her with a diamond ring and "Will you marry me?" scrawled across an underwater writing tablet while scuba diving off the coast of a tropical island, or propose when you reach the top of a cliff after a long day of competitive rock climbing. If you're really daring, get down on one knee before you and your girlfriend fasten bungee harnesses to plunge into the unknown. Once your girl inevitably says yes, take a leap of faith together and experience a mixture of emotions that will result in an all-time natural high.