I miss the early patch days of New Vegas when an enemy would fly up 50 feet in the air like they had a jet pack on. Also saw a floating garbage barrel once too.
During my second or so playthrough, I ran through Quarry Junction without knowing about it. I was a little too... focused on the Gomorrah billboard that was there (http://th01.deviantart.net/fs71/PRE/f/2010/323/9/a/gomorrah_fallout_new_vegas_by_fragocon-d3360x5.png) before I heard growling noise behind me, only to turn back and immediately got pimp-slapped by a Deathclaw. Scared the crap out of me, but it was a good laugh.
I still think Obsidian put that billboard there on purpose.
I don't believe that is random, it is scripted. Happens in all my playthoughs. Same with NCR guys throwing up and chearing on the women in front of Gomorrah.
But I agree it is funny.
I walked into Vickie & Vance Casino, and found Primm Slim standing in a garbage can. Actually, it appeared that he was the garbage can from the waist down...
Random? As in not scripted?
I had half of Novac fail to load and instead become a giant hole in the ground one time. I had to reload a save that was back at camp searchlight to send that poor dinosaur back into the realm of reality.
One time I was fighting some legionaries and one of them got stuck inside of a rock. I had to run away from him to get the game to shove him out of it, since after putting several mags from both my rifle and my pistol into his head sticking out of the rock, I sadly could not harm him.
Ive also had NPCs walk from a interior into the overworld, and then they dissapear with my pipboy quest marker telling me that they are on the other side of the map, trying to make their way to where the game told them to go, despite falling in some sort of space time abberation and ending up far way from Helios One.
New Vegas barely crashes for me, but it does bug out in extremely weird ways. Part of the charm of Bethesda games.