Check also in the Northeast forum as the DC metro/Northern Virginia area is split up. Local bike shops include Spokes,etc (Vienna location), Bikes @ Vienna (more 'bents, folders, and other unique rides). Don't know if they do any shop rides. I know Bike Lane's Reston Town Center store has shop rides. No idea if anyone rents road bikes. Performance Bikes has a shop in Tyosns (on Rt 7); they definitely do not rent anything. The local racer scene has a email list (search google groups for mabra) and someone there might have a bike to loan/rent. Some teams to check out include NCVC, Evolution. Rides - Reston Bike Club runs weeknight rides Tuesday (Reston) and Thursday (Herndon) and on weekends (
see website).
Potomac Pedalers Touring Club has a wealth of rides every weekend and some weekedays. Also check
www.bikewashington.org for possible routes.
Tysons itself is an over-developed suburban traffic & construction hell-hole built by people who hate anyone not in a car and hate the car drivers, too (they don't want anyone to feel neglected). But just south of you in Vienna is the Washington & Old Dominion (W&OD) trail, which runs 10 miles east towards Arlington & DC and 34 miles west to Purcelville and some really nice roads in Loudoun County. If you score a bike and are determined to ride from the Embassy Suites, your options are either Gosnell Rd and work your way south (try to stay off 123/Chain Bridge/Maple Ave) to the W&OD. Or if there is a way to go west along 7 (the service road is gone but the parking lots may connect somehow) towards Westwood Center Dr & Ashgrove Lane. There is a pedestrian and bikeable paved path (visible on Google maps) connects the end of Ashgrove across some woods to a subdivision south of Tysons, you can then use side roads to work your way down past Old Courthouse Rd (I'd minimze my time on it) to the W&OD area. If you drive to the W&OD, there is plenty of parking along the trail in Vienna west of Church St. Spokes & Bikes@Vienna are just a few short blocks away. Have a good visit.