Do this now: Hilton HHonors early summer promotion
/Registration is now live for Hilton's first summer promotion, whereby you can earn double points or double miles for all paid stays between May 1 and July 31, 2014.
Once you've made your selection, upon registration, it can't be changed later.
The Points Guy helpfully reminds us that since January, the only two Hilton HHonors earning options have been "Points & Points" and "Points & Miles."
So whichever version of the promotion you choose, make sure you have the corresponding earning preference selected!
In any case, register now, before you forget.