I just came across a site with outstanding interactive jigsaw puzzles, go to Jigsaw Explorer if such puzzles turn you on.
For example, this tower at Beget, Spain (with the option selected to remind you what the “box top” is for the puzzle):
Actually, rather than jigsaws my definite preference is for word puzzles, not only as a consumer but and in the past I’ve created some crosswords that were based around various themes in information technology.
Unfortunately they’re now offline after a redesign of the site where I created them, and the site owner isn’t interested in bringing them back to life.
I really should create some more of these interactive crosswords, this time on my own site so that nobody can take them offline. I used the highly recommended Crossword Forge to build them:
Crosswords take a long time to compile, especially when the choice of words is confined to a theme rather than the general language. Software like Crossword Forge significantly eases the burden.