A very interesting topic, especially given that I am a time traveler. I have seen a lot of things, but I'll try to go over the ones you've mentioned.
- OJ trial verdict - I wasn't actually in this timestream when this happened, so I'll have to skip it. I suspect I would have rolled my eyes.
- Princess Diana death - I was in a Boston Pizza when I heard about this. To me, this only happened about 3 months ago, so it's still rather tragic. One of her boys is getting married if I recall correctly.
- 9/11 - Interesting, as this was one that I initially heard about when I visited the year 2005, and then went back to 2001 later. So I knew it was coming, but was unable to prevent it. Paradoxes and what not; tricky. I can remember being shocked about it when I first heard about it, but seeing it in person was even more stunning. I was at some random girl's house when I flipped on the TV and saw it though.
- Canada hockey gold in Vancouver - I was at a pub in Vancouver with some friends. One of them was from the year 1914, so I had to keep trying to explain all the rules. But boy was it exciting. I did not know at the time that we were going to win gold, so it was amazing!
- Gretzky trade - Coincidentally, I actually found out about this when I was in 2010 watching the Olympics. I'm still stunned, but not as stunned as I was at the Crosby trade!
- Flames eliminating the Canucks in OT, game 7, 2004
- I was at a pub in Calgary at the time. I whooped and jumped up and down. I try to avoid sports scores unless they're live as it ruins it for me.
- Challenger explosion - I was originally (in the very early stages) scheduled to be on this flight. Scary stuff. I don't think I created any paradoxes by finding out about this one ahead of time (in 2114, of all times!) as I was disallowed due to medical reasons. I did see it on the television though. At my home.
- 1st Iraq Gulf war - I actually can't remember where I heard of this one. It wasn't nearly as bad as the 3rd Iraq war though, was it?
-JFK assassination - Heard about it through an army contact as I was in West Berlin at the time. This is one that every time traveler knows about already though, so there was no real surprise there.
-man on the moon - I've been to the moon 6 times, but I have never been present in that time for the first trip to the moon. Supposedly very magic at the time, but I think you'd have to be a contemporary to get the full effect. The moon's a big tourist site though.
-Berlin wall - I was eating nachos in a sports bar in Phoenix. Good nachos.
Some other ones:
William of Orange conquers England - I served for a brief time in his army, so I helped conquer England. Neat, huh?
President Benson's execution - I actually won tickets to this in an audience lottery, but I had to miss it. Shame, because it's not every day you get to be present first-hand at such a huge event.
Martin Luther - interesting times, as I knew him quite well. I tried to convince him to go for an even 100 theses, but he wouldn't listen.
I'll check the future responses to this thread right away so I can reply. It's faster if I do that.