I've always been told that a script should be at least 120 pages, which is generally 1 page per minute of film.  Well my question is:  If a scene involves doing a single thing for one minute, should you just write that one thing and then skip down to the next page leaving a ton of white space or just continue the format as it is?  

No.  I've never seen that before ever in any screenplay.  And that minute per page thing is only a gauge to go by.  Don't be too dependant on that because it could really mess up your story.

Good example.  Donnie Darko was only a 92 page script, but a 128 minute movie.  And Richard actually had to take stuff OUT.  So it could have been almost 140-150 minutes if everything was in.

So it doesn't always mean one page = one minute.  Describe the sequence or scene as best as you can and move on.  Just make sure your scripts are at least 85 pages though.  

The one page=one minute rule is a general guideline.  It can't always be accurate, depending on what exactly is on the page.  Action sequences take up a lot of page space but only add up to seconds on the screen.

Don't leave pages blank.


Phil

It also depends on the director and how the scene in ultimately filmed. In the Return of the King script, that bit where the fires are lit on top of the mountains between Minas Tirith and Edoras was one sentence in the script, but took up several minutes of screen time.

Don't worry about time when you're writing. It's a nice gauge, but can be flawed and thrown off by a number of factors.

Also - if you were told that a script HAS to be atleast 120 pages - you've been misguided.

The rule of thumb is no less that 85-90, no more than 120.

All this stuff refers to a 'spec screenplay’ written by an agent-less writer or one without representation who submits speculatively..

Once you're a successful screenwriter you can pretty much do what you like depending upon how you pitch your ideas and how many drafts you go through and how the production company and it's producers specify requirements...