At approximately 7:30 P.M. I and my father and some neighbors were out in the street chatting when a large cylindrical object drifted toward us from the northeast at about 800 feet.

It was completely silent and had several circular, symmetrically spaced windows [?] which I considered analagous to portholes.  These portholes were of different colors and changed to different colors at regular intervals.  
When the object arrived above us it stopped and remained stationary for the duration of the time we observed it, approximately 30 minutes.  
We all watched it and discussed it's properties and no one could ascertain what it was.  One of the observers was a pilot with TWA.    
After watching it for about 30 mins. everyone went inside and as far as I know none of us has ever reported it until now.  Thank you.
Witness indicates that date of the incident is approximate.  We have changed the time above; 7:30 p.m. is 19:30 hrs. on the military time system.  PD