Color-on-color rivalry games are the best
In the case of USC-UCLA, however, the reason USC worse their home cardinal and the Bruins wore their home blues is because they both actually
were the home team.
Before they moved into the Rose Bowl in 1982, UCLA called the LA Coliseum their home stadium.
Edit: when UCLA moved to the Rose Bowl, USC wore their away whites when they played at the Rose Bowl, and UCLA wore their away whites when the game was at the Coliseum, as per NCAA rulezzzzz.
However, Pete Carroll and Rick Neuheisel revived the tradition of both teams wearing their home jerseys starting in 2008, even though it was against the NCAA rules. IIRC, the penalty was a loss of one timeout. On 2008, the game was at the Rose Bowl, so USC got penalized a timeout, but Rick Neuheisel immediately took a timeout of his own so both teams only had two timeouts that half. I recall that fans on both sides loudly cheered this "fuck the NCAA" stance from the coaches.
After that season, the NCAA allowed teams to wear home-and-home jerseys for rivalry games, so long as they wore "contrasting colors."