Um, none? Repeated player stupidity that keeps getting them killed – sure. Chaotic events that keep happening – definitely none. Sorry, no interesting answer here for the day. Mind you, I think that this may because I act as a bit of a buffer to this in my game. If random events occur and I see a pattern emerge, I tend to squash it. In the same way that my games may have an ancient red dragon (for example) rolled randomly, if the next couple of encounters are also scaled horribly for the players then I will mitigate them and lessen the encounter.
Random
I am the reason that recurring random events are rare in game. I as the GM keep my eye on that stuff and destroy it. Sometimes in game a player will seem to be selected more than another for random effects but that is just a transient effect of the dice. In fact, there is a lot of pattern in chaos theory. There are papers and papers on the subject in mathematical and scientific circles so it is expected I suppose!
Regardless, the random thing in this question is not what happens in my games – sorry! Keep rolling!