Whilst not a professional mathematician himself, the books and puzzles of Martin Gardner inspired a great deal of progress in mathematical research, including tilings, hexaflexagons, Steiner trees and no-three-in-line problems. A Victorian equivalent might be Henry Dudeney or Lewis Carroll.

My question is: who would you say is the modern Martin Gardner? That is, which recreational mathematicians can be said to a) be popular with the public and b) have inspired new research-level mathematics?