What movie has the shortest running time?
I guess it depends on what you count as a movie. There’s Dickson Greeting, which clocks in at 18 seconds (not counting intermission).
I think I’ll move this thread to Cafe Society.
Kinda subjective, because when does a short film become a movie and vice versa? I don’t think this question can really be answered.
Teebone
Can someone give at least some figures? How about the shortest movie that made at least a million dollars at the box office? Or the shortest movie that won an academy award?
There is more going on in Bruce Conner’s Ten Second Film then in most movies ten times its length. 
I’ll see if I can get back to you and your questions, aeropl.
OK, of the 100 biggest money-making films of all time (adjusted for inflation), the 70-minute Bambi (ranked #31 with $412M) clocks in as the shortest. In fact, the 7 or 8 shortest on that list are all Disney animated features.
You are unlikely to find a shorter Oscar-winning film than the 4-minute animated short The Critic (1963) which features a very funny Mel Brooks as an art critic.
To qualify officially (for award recognition, or film festivals) as a ‘short film’ it has to be under 15 minutes. To qualify as a ‘feature length film’, it has to be over 60 minutes (I think).
This is why there are rarely theatrically released films of intermediate lengths. If one does get made somewhere between those lengths, it tends to be intended for television or video.
This doesn’t answer the OP, except semantically perhaps.
Feh! That’s von Stroheim’s Greed, compared to Fred Ott’s Sneeze!
Bambi meets Godzilla! Less than a minute long, if I remember correctly.
Having worked at plenty of film festivals, I can say that this is categorically untrue. The time limit that the Oscars uses is 40 minutes (less than = short, more than = feature), and I have found that this is more-or-less the standard used in other venues/situations, too.
After I posted that, I had a deeper look around and saw that the rules vary according to country and individual festival etc, so Archive Guy, you are more or less right.
But I was told those facts I quoted by a Director who was being very careful about the length of his piece (down to the final frame) so that it would qualify as a short film - exactly 15 minutes, not a frame more.
This was in New Zealand, about five years ago.