I'm a patroller, so I see lots of skiing related injuries... some of the most memorable ones are:
During practice for a big air comp some kid under-rotated a 9 or 7 and basically his head broke his fall. He immediately started convulsing and pretty soon his face started turning blue as he was struggling to breathe, so I inserted a nasal airway (little rubber tube that goes into your nose). That was painful enough to help bring the kid back into some level of conciousness and allowed him to breathe. That was the first time I had ever put the medical chopper on standby. Although the kid was back at the hill later that night to watch the rail jam.
Another good one last season was a broken tib/fib... both of the bones located in your lower leg. The guy was just cruising groomers and making turns when his leg snapped right at the top of his boot. His foot was backwards when I got to him...
My friend passed out at the peak of Crested Butte because of the lack of oxygen, but there was no way we could know that was what the problem was, so as my other 2 friends went to get ski patrol I stayed with her and it took a good 20 minutes or so for patrol to hike up to the top. Probably one of the scariest moments ever. It sucks when you have medical training and there is still pretty much nothing you can do for your friend. She was fine once she got to a lower altitude and got warmed up.
Those are some of the ones that pop into my mind right away. I'm sure I'll think of some more.