The Raiders interviewed Broncos DC Jack Del Rio for their head coaching vacancy on Sunday, according to the DP's Mike Klis. Per Klis, the Sunday interview required special permission from the Broncos, as the window for interviewing coaches from teams on bye weeks had closed on Saturday night.
While logistical issues apparently prevented a Saturday meeting, it's notable that Denver gave their primary historical rivals an extra day to interview Del Rio. Such an accommodation would have been unimaginable back when Al Davis was around, or during the pre-Peyton Manning days when the Raiders actually stood a chance of beating the Broncos in a given game.
FWIW, Jerry McDonald of the Contra-Costa Times surprisingly thinks interim coach Tony Sparano is the frontrunner to land the Raiders' permanent coaching gig. McDonald thinks Del Rio, Pat Shurmur, and Darrell Bevell are the next likeliest candidates to be hired by Mark Davis.