In no particular order: Ski Trip by Rhapsodista
I love this so much because it's something unlike all the rest of the stories. That usually pertain to case fics or something FBI related this is simply a vacation done terribly wrong.
I also love how she inter spreads little scenes about Don or Charlie reflecting on one another, coming to some understandings themselves about the other.
This also doesn't disappoint in the H/C department. Charlie's really sick and it's only made worse by the fact that Don and his team went out skiing and had to take shelter in an cave to escape the storm. Charlie's sick, worried about where his brother is and isn't doing well. What happens? Well you have to read for yourself ;D