Fellow Sudokians!
Are you aware of this intriguing set of 101 puzzles depicting a variety of objects, say a house, padlock, cannon, and 98 others? Each puzzle can be easily referred to by what it represents. You could solve, for example, the "house" and ask someone if they managed to crack it too (something you can't do with a random puzzle). In the book, every puzzle is accompanied by a story on the depicted object. Hence the "padlock" puzzle comes along with a short story on Harry Houdini, an extraordinary escape artist famous for opening any lock he was challenged with. The "cannon" grid, on the other hand, comes with the story on the early attempts of shooting objects into space by enormous cannons (having hurled projectiles to the heights of 112 miles, the US military abandoned the project in 1967). You don't see this kind of puzzles often -- they can be heinously difficult to design.
All in all, these 101 grids (some easy, some hard) constitute a unique and worthy rite of passage for every serious Sudokian.
The good news is that there is a website with a selection of free puzzles from the set. Could I tease you by presenting a link to a video that will lead you to the website!
Peace!
Oscar Seurat