In the car:
Kasabian - West Ryder Pauper Lunatic Asylum
Bach - Musical Offering
At a "rehearsal":
Wagner - Prelude to Act III of Die Meistersinger
Elgar - Cello Concerto
Brahms - Symphony No.1
The "rehearsal" was the Berlin Philharmonic in the Sheldonian Theatre, Oxford. It was a phenomenal experience - the Brahms in particular was amazing. A picture of the event can be found here!