Flying saucer seen by 100 people at drive-in theater in Denver

Peter, I thought you might like to hear about this incident even though it  took place about 25 years ago.  It happened to my wife, not me, but I have a better command of the language and will relate exactly what she described to me.  It is a fascinating event.
She was at the "Mile High Drive In" theater in Denver, Colorado.   Although my wife doesn't remember the year, she does remember that the movie playing was "Dr Zchivago".  Everyone there suddenly saw a huge flying saucer slowly rising up behind and somewhat to the left of the screen.  Everyone got out of their cars and watched as this thing slowly rose, with lights circling its perimeter, then came to a complete standstill, hovering.  As they continued to watch it just sit there, it eventually then tilted to a 45-degree angle and then suddlenly just ZIPPED out of sight in the blink of an eye.  Everyone was astounded.  That's it.  And of course she's been a believer ever since.  There is, however, an interesting little footnote to this event...
About a year ago, my wife was watching an old UFO docu-drama on tv, and some lecturer or news reporter described exactly the event she witnessed.  This leads me to think the event was indeed documented, but I have searched the internet, and cannot find any such record of the event.  I would be extremely grateful to you, Peter, if you could provide me with any information about this event.
Date is approximate.  PD