8th grade! I make them do logic puzzles all the time, too.
Anything involving reasoning or problem solving, really. Gotta get them out of the "video game" rut and into some creativity.
Plus, right now we're doing intro to algebra and equations...mostly writing equations from word problems...and THAT one is awesome.
Of course, I don't expect any but the top few to get it, so we will go over it as a class to investigate how it works.
I also gave them an "impossible puzzle" to solve. I'll find the link to the website so you can see...it has 250,000 incorrect solutions, and only 45 correct ones! It drives them insane, no one has figured it out yet, (except Paul, butthead) and they ask to work on it anytime we have a spare moment.
yeesh. I was rambling. Sorry, I just LOVE my kids.