You need to register to take part of this new promotion of Hilton HHonors:
With the More Points promotion from Hilton HHonors™ you’ll earn 1,000 Bonus Points for every night plus an additional 5,000 Bonus Points for every weekend* stay of two nights or more at participating hotels and resorts through March 31, 2012.
*Weekend is defined as Thursday through Sunday.
There’s also a list of non-participating hotels. Please check carefully. Dozens of U.S.-based hotels are excluded as well as the following worldwide properties:
- Hilton Eilat Queen of Sheeba hotel, IL
- Tel Aviv Hilton, IL
- Hilton Namhae Golf & Spa Resort, KR
- Hilton Royal Parc Soestduinen, NL
- Hilton ParkSA Istanbul, TR
The More Points FAQ site explains the promo in detail. Check also the complete T&C.