Loading 59 AIs at Lemans, at night, can be pretty fun. LMPs from the ISDM mod and GTs from the SCC mod. The SCC cars aren't all that great physics wise, but they sure look good as you're blasting past them in the Porsche LMP2.
The new(ish) Daytona Prototype mod can be fun, and Niels' Vette is about as good as it gets w/ Real Feel. Be sure to try all the Virtua-Lemans team tracks, and of course the 'Ring is epic.