Starwood has a an offer for California residents who book paid nights in California – every 3rd night is free. The promotion code is Z3H.
Offer is valid at participating Starwood Hotels & Resorts in California, please see participating property list.
Offer is valid for stays booked and completed by December 31, 2013.
Reservation must have a three night minimum length of stay.
Advance reservations are required and may be made online or by calling 1-866-716-8147 and mentioning Promotion Code Z3H for Hotels and Z3R for Resorts.
For every two nights paid receive one night free.
Only available for arrivals on Thursday-Saturday at Hotels. All days of the week arrivals are valid at Resorts.
These offers are based on Starwood's best available unrestricted retail rates.
Advance purchase required. Credit card will be charged at time of booking. Reservations cannot be changed, are pre-paid and non-refundable; if cancellation takes place, guests forfeit total room charge plus tax.
Rates are per room, per night, based on single/double occupancy and availability at time of reservation and do not include additional per room, per night charges that may be imposed or state/local taxes.
A limited number of rooms may be available at these rates.
I did not have time to check how competitive these rates are against other rates on spg.com but it could be a good offer.
For the CA residency requirement it should be enough to claim that in your profile.