Setting the scene:
The Top Gear studio is basically an airplane hangar with the bench seat of a late-model Jeep Cherokee serving as a couch. Since you probably can't fit a Cessna Citation in your living room, we suggest sticking with the Jeep seat. After that, let your imagination run wild with anything and everything car related: chrome rims, posters, fuzzy dice, fenders from a Mustang, blinking headlights, used seat belts, shiny exhaust systems, windshield wipers and vintage gas station signs. If your wallet can handle it we also recommend a custom 1957 Chevrolet rear-end couch. Hook up your PlayStation to the big-screen TV, and pop in Need For Speed: Hot Pursuit. You might even consider an auto scavenger hunt to start off the party if enough guests are up for it. Invitations can be made up to look like blown-up driver's licenses, and party favors can be anything from gas cards to DVDs of the original BBC version.
Racing suits, helmets (think Stig), plaid shirts (think Adam and Rutledge) or Top Gear T-shirts.
On the menu:
Takeout. We recommend buckets of KFC (dibs on holding it in our lap for the ride home).
On the hi-fi:
It's impossible to choose! 409 by The Beach Boys, Chevrolet by ZZ Top, Drive My Car by the Beatles, Greased Lightning by John Travolta, Dead Man's Curve by Jan & Dean, Hot Rod Lincoln by Johnny Bond, I Can't Drive 55 by Sammy Hagar, Red Barchetta by Rush, Pink Cadillac by Bruce Springsteen.
One of the best parts of Top Gear is the celebrity test lap, so let's move the party to your nearest racetrack that allows civilians to use it (for a huge fee, of course) and give everyone a chance to do a lap in celebration of America!