Alan Ling: I met Alan in Math 145/147 as an undergrad. He is very smart. Or, was it very lucky. Alan can solve any problem by inspection.
Jeff Shallit: My Ph.D. supervisor. Has more books than I will ever read. Probably would like me to read all his books.
Charlie Colbourn: A combinatorial king. I took 2 courses from Charlie as an undergrad, and my wife's freinds father was his supervisor. Isn't the world small (sort of)?