I don't know how useful it is as an account because i was somewhere around 8 or 9 years old. (i'm 29 now, so we're talking around '96-'97), so i can't give a specific date or time and of course my testimony is not reliable. i witnessed this with my sister who is 6 years older than me, although when i've asked her about it recently, she told she's seen so many ufo's in her life they all kind of blend together, and while confirming the event seemed hazy on the details i offered her.
as best as i can remember it was after dinner and i was playing with my sister in the front yard. i distinctly remember calling my sister over to show her a spider i found in a shrub that was hurriedly spinning up a captured bug in it's web. this was in san jose, california where the winters are pretty mild, but i feel like seeing the spider outside probably means it wasn't winter. i was kind of transfixed for a bit watching the spider work, and it had gotten dark. that was when we hear a loud noise from the sky. in my child's memory it sounded like a giant laser, like a sonic boom, but... higher pitched? the sound was accompanied by an object that seems to fly across the entire sky in only a second. it was a triangle rapidly spinning. i couldn't tell if it was a flat triangle or a triangular prism, as it seemed to be spinning on multiple axes, like a gyroscope. but the most distinctive thing was the light it created, it was bright red- or it could have been more orangish, or pinkish, but for the brief moment this thing was careening across the sky, it seemed to light up the whole world in a red hue which lasted for split-second after the object had flown out of sight, then faded away. i have no idea how high up it was but it seemed to me to be around the same height as airplanes fly.
i remember going inside and being surprised our parents didn't hear it, because it was loud! i remember not registering what we saw as a "ufo, like on the x files" until my sister told me that's what it was, and then being terrified. i remember us describing it to our parents and them suggesting that because we described it as coming from the west or north-west that it might have come from moffett field air base, just to the northwest of us in the blossom hill neighborhood of south san jose. i remember asking classmates about it the next day and getting blank stares. it's always bothered me that what i saw was so loud and so bright and over such a densely populated area that it seems impossible that this could have been an experience limited to only me and my sister. whatever this was, it's not something you would miss if you didn't happen to be looking up at the sky at the right moment. it was the kind of thing you'd think would be more likely to draw neighbors out of their homes saying "what the hell was that?"