Bonus bucks are why I stay at FS Marriott properties on weekends in the DC area since they bring down the effective rate to an amount lower than CY or FI. I get and use a $100 coupon with every two night stay on weekends.

For many FS Marriott hotels in the DC area, you can get a free or reduced rate for a full breakfast buffet on weekends. In my personal experience:

Fairview Park Marriott - have almost always gotten a free buffet and have only had to pay for the tip (as gold and platinum)
Tysons Corner Marriott - as a platinum I pay for only the tip (not sure about gold members)
Washington Dulles Marriott Suites - no lounge, but a full buffet is available for a reduced amount (including tip it is between $4-6, with weekends being a bit higher) Healthy start breakfast buffet is always free for gold and platinum members, and you can order room service for it as well.
Westfields Marriott - full buffet is available for just the cost of tip everyday for gold and platinum members (since they lack a lounge)
Gaithersburg Marriott - no free breakfast for gold and platinum members
Crystal City Marriott - free breakfast for gold and platinum members. They treat gold and platinum members well. I got my first suite upgrade here as a gold member a few years ago.