125 mph in an S-type Jaguar 4ltr V8 on a Slovenian motorway, between Ljubljana and Trieste - I didn't mean to, but the thing was so damn quiet!
The most fun, though, was doing 115 on the Autostrada Adriatica in a Porsche Boxster with the top down - even if I was overtaken by, amongst others, an Opel Astra!