I'm browsing through Knuth's The Art of Computer Programming (Volume 1, Volume 2, Volume 3), because it's Spring Break, so I have time. I'm reading the mathematical bits, which are perhaps half the work; I'm less interested in the algorithms.
Anyway, we find on page 158 of Volume 2: "Some people spend a lot of valuable time playing card games of solitaire, and perhaps automation will make an important inroad in this area." This is part of Chapter 3, on the generation and testing of random numbers. Of course, this book was published in 1969; Windows Solitaire didn't exist then. (It's also amusing to see Knuth describing things that will be in, say, Chapter 10; he's currently working on Chapter 7, which will be the first half of Volume 4.)