First Hilton devalues everyone's points and now they offer triple points for the Hilton Q3 2013 promo.
From July 9 to Sept 30, 2013, you can get triple points for Friday/Saturday/Sunday nights. Other days get double points.
You DO have to sign up to get the bonus points.
Of course there are lots and lots of hotels that DO NOT participate if you read the fine print. Click here to see the list of non-participating hotels. Hopefully the Hilton hotels that you are staying at are not on the list.
See the frequently asked questions here: LINK TO FAQ
Here are the details from Hilton's website: