I remember going to a Giants baseball game with my mother. It was a Sunday, and the 49ers were playing the Rams in Los Angeles.
My mother was listening to the football game on the radio , and feeding me and a friend updates as the game progressed.
I remember, continually bugging my mom to tell us what was happening, and having her say, "Nothing yet" or "TV Timeout" or "Still lining up", while pitch after pitch and batter after batter would come and go.
I found it quite fascinating that all of this action was occuring in the baseball game while the football guys where still figuring out what to do next.
I also have a vague memory of a radio station timing a football game with a stopwatch. Starting it as the "snap" and stopping it at the "whistle" I believe the total was approximately 9 minutes. 3 hours of mind-numbing "action", boiled down to 9 minutes of actual play. This radio station compared their results with "America's Pastime" (pitch to umps call) and the total came to 45 minutes.
Major League Baseball features Condensed Games showing only pitches that result in game action on their website. These condensed games run about 20 minutes.