If they like a challenge, they'll love the puzzles that are available at Findgift. There are brain teasers that will make them have to think harder than they ever have before, there are 3D puzzles that are fantastically fun to take apart and put back together, there are puzzles that will look wonderful on their shelf, there are puzzles made of wood, and there's so much more. It's a gift idea for the person who believes they can solve any problem.