Cape Ring Full Track: The series of turns after the loop until the starting line.
Trail Mountain: The high speed uphill section at the begining, until the right hand turn after the first tunnel.
Nurburgring: From Flugplatz, going through Aremberg, all the way to Adenauer Forst. Those are my favorite sections of the old ring.
Route X: The part where you go really fast.
Top Gear Test Track: From the Line all the way to The Follow Through.
Le Mans track: From the Porsche Curve to the New Maison Blanche turn.
If I think of more turns that make me smile, I'll put them here.