Hal Finney was in the same fraternity I was in at Caltech - Page House. He was a couple doors down the hall. Caltech was full of smart guys, but Hal is a standout smart guy among them. There was once an informal contest with MIT to write a Gomoku game playing program, with of course a playoff. Hal wrote the whole program in a weekend and it trashed MIT's program.
Hal was a good friend to everyone, even immature jerks like I was (and hope I am no longer). He'd stuff as many as would fit into his VW bug and take us all out to Tommy's at 3AM for burgers.
I am deeply shocked by this development. Hal, my best wishes go to you and your family.