Originally Posted by PedroNY

There are also Diamond and Gold Challenges that Hilton runs from time to time. You do need to stay a few nights, but if you already have a credit card that gives you Gold, it will be easy to get Diamond as well.

Amex Surpass and Citi Reserve both give you Gold w/o any spending, and once you spend $40,000/year you get Diamond for that calendar year + 1 more calendar year + 3 months. So if you spend your $40,000 now, you will have it for 2015, 2016 and through 3/31/2017.

Cheers,

PedroNY