Random promo that was pointed out to me earlier today... If you have a Signature VISA Card, you can get temporary HHonors Gold status through August. After getting the temporary status, if you stay three nights between now and the end of August, then your status is extended until March 2013. This Signature card does NOT need to be a Hilton card. I just tried it with my Marriott card, and it worked like a charm.
It's a pretty sweet deal. And while it doesn't say anything about this in the promotion, my friend (a HHonors Diamond) tried to do the promo, and boom - 5000 HHonors points magically showed up in his account. So it looks like if you already have HHonors Gold or better, they'll hook you up with some points as a consolation prize. Give it a shot and report back!