I had my life flash before my eyes - it really can happen.
It happened to me once when I was about 7 years old, and I had fallen out of an apple tree. It was a height of maybe 10 feet, but at the age of 7, I thought I was going to die. In the few short seconds as I tumbled to the ground, I saw images in my head (not with my actual eyes) of my whole life. The images came in no specific order, and just kept changing. Some were just flashes of people and some were "clips" - little snippets of events like somebody saying "I love you". It was a very happy and euphoric feeling of joy and love, and it was a one of a kind experience. When I hit the ground, the flashes stopped, and I couldn't believe I was alive. I was astonished by how many things flashed - it seemed like hundreds of different things. I was astounded of how many images I saw that I had forgotten about. It seemed like the experience must have lasted for several minutes, but obviously, it was just a second or two. A lot of the images were just images of friends or families smiling, or telling me they love me, etc. Some of the flashes were of nothing special, but none of the flashes I can remember were negative (i.e. like getting punished, etc.). Also, I saw all of these flashes in the first person. In other words, I saw everything through my own eyes, and not from out of body.
In the movies, they depict this by showing minutes of memories in a split second. First they show the bad event coming (i.e. a bullet heading towards a victim), and then the slowing down of sound and video, then several minutes of flashbacks before the tape speeds back up and the bullet hits. It's not a bad representation, but I would say the number of images and recollections are much greater than a movie could portray.
It was such a positive experience, that I hope I can experience something similar before I go...