Does anyone know of the best way to find 24 hr. coffee shops or restaurants (other then Denny's) in the Southern Cali area?

I’m always trying to find new places, cafes, coffee shops, etc. to go to late at night in Southern Cali. However, I can’t seem to find any website or database online. The only 24hr coffee shop I know of is in San Diego, and I’m trying to find one that is closer to home (Riverside County).