I've made one real ace. It was on a blind hole.
But at little tiny Presidio Hills in San Diego, I've had 3, the longest of which was 50 yards. One was on the first hole with my mom watching. Another was on the 6th, which now that I think about it is totally a reverse Redan of 50 yards. The remaining one was on #18 with a putter.
I don't think I've seen one in a tournament, but I have witnessed an albatross at #12 at Kingston Heath. The guy played 12-14 in five-under-par.