Through December 31, 2013, American Express is offering US Platinum Cardmembers (both personal and business) complimentary Hilton HHonors Gold status. To take advantage of the offer you just have to call American Express customer service and give them your Hilton HHonors account number. Your status should be updated instantly, and will be valid through all of 2014.
Hilton Gold is one of the most useful mid tier status levels, since it includes complimentary internet and breakfast/lounge access, which I consider to be the two most valuable elite hotel perks.
There are cheaper options for getting Hilton Gold status than acquiring an American Express Platinum Card. For example, you can buy a Milepoint premium membership for $49.95, which comes with HHonors Gold status. Alternatively, for Gold status long term it’s tough to beat the Citi Hilton Reserve Card, which comes with Gold status for as long as you have the card, and has just a $95 annual fee.
(Tip of the hat to The Points Guy)