Alan Turing's Contributions to Computer Science
I did not know of these until recently.

1) The LU decomposition of a matrix is due to Turing! Considering how fundamental LU decomposition is, this is one contribution that deserves to be highlighted and known more widely (1948).

2) Turing was the first to come up with a "paper algorithm" for chess. At that point, the first digital computers were still being built (1952). 

Chess programming has had an illustrious set of people associated with it, with Shannon, Turing, Herb Simon, Ken Thompson, etc. The last two won the Turing Award. And Simom, of course, won the Nobel as well. (Shannon came up with a way to evaluate a chess position in 1948.)