Deal Link:
https://www.hiltonhhonors.com/5887_04212016/
Expiry: Aug 31, 2016
You can earn Double Points when you sign up and stay at any hotel between May 1 and August 31, 2016. There's no limit to how many Points you can earn. Online registration is required.
Also remember, you can get 100% more points when you buy HHonors points before Jun 3, 2016:
http://www.canadianrewards.net/2016/04/get-100-more-points-when-you-buy.html