Smichovske nadrazi bus station is a station where you get off the metro and have to continue by bus to the outskirt of Prague. Kinda last bit of a city. (Ok, that's a little exaggerated but you get the idea :)
BTW, there's so many things to do this weekend in Prague. There's Code:mode - Prague Free Fashion Weekend, Fotojatka - festival of creative and documentary photography in Aero cinema and also that Obama in Prague thing (good to know that on Sunday all presidents have 50% off in Aero cinema :)
... and still, the best place will be at our us-cars meeting in Jizbice. We even have a Facebook page :)