Bill - I'm with you there, a good friend invites me to Sand Hills every year, it will happen soon. Turned down a long weekend at National Golf Links in August with good friend plus a boys trip to Congressional, Chechesse and Kinloch in late Oct, this is a going to be a 2013 trip though!
Wisest turn down? Arrived at Merion at 4pm straight from the airport, had the option of running around the course to fit in the round (@ $220 plus caddie) or play a 4 1/2 hole loop, drinks and dinner on the patio and a proper tour of the clubhouse. This turned out to be a splendid evening and a cherished memory.