Almost a year ago, I wrote about how you can get the Starwood Preferred Guest Gold with just ONE night stay instead of 25 nights. All you need is a World MasterCard and to register for the relevant promotion HERE. Upgrade to the Gold status will take up to 4 weeks after your stay (although from experience it takes about a week). Do remember that you need register for the program first, and you have to book directly with the hotel (not through Agoda or online travel agents) in order to qualify for this promotion. Also do note that status earned after 1 April of each year will last longer in absolute terms.
As the promotion is ending in a few months (12 July 2015), I recently convinced a friend to take advantage of it and after signing-up, he received this offer after a few days of inactivity. 1,500 Bonus Starpoints and getting Gold status with just one night stay is a pretty sweet deal if you ask me.