Seen a few things, but the most exciting, in a trouser-wetting sort of way, was back in 1985. I was in freefall, descending past about 5,000 feet. Straight ahead of me, about a mile distant, and I reckoned at about 200 to 300ft AGL, was a rapidly approaching dot. By the time I'd fallen another 1,000 feet, probably less, the 'dot' had materialised into a bl***y big HS Buccaneer, on an exact reciprocal of my 'heading', and it flashed past directly below me! If I'd exited the aircraft a second or so later, I'd very possibly have ended up as his windscreen sticker, as the jet screamed right across the centre of the DZ!
I do believe the crew, on a delivery flight, got a right royal roasting for overflying the centre of an active parachuting site.
Me? I just got a cleaning bill!