Ask HN: Fun challenges for a 9 year-old math whiz?

Friends of mine have a 9 year-old son who recently scored in the 98th percentile in his school's math tests. The teachers now want to put him in 7th year math class (he is in 5th year) and apparently sent him home with some multiplication tables which he memorized instantly as he also has photographic memory.

It doesn't help that he lives (and goes to school) in a rather rural part of New Zealand, an hour outside of Wellington. Neither does the fact that his school recently fired their principal and is in a bit of turmoil ever since, leaving less time for teachers to focus on individual kids.

(Moving to a different town or having him commute to a different school aren't really options for his family at this time.)

When I heard about all this I was wondering if there aren't better ways to engage him and allow him to develop his skills, rather than memorizing tables. I was thinking that something less dull, more animated and colorful would be better suited to give him some inspiration and encourage him to pursue his strong suits.

He doesn't know his way around computers particularly well (yet) but he likes playing games on his PSP and so I thought games might be a good angle to get him started on something fun to do with computers.

A few ideas I've had so far:

* Lego Mindstorms

* Arduino Starter Kit, BASIC Stamp or similar

* MIT's Scratch ( http://scratch.mit.edu/ )

* Chess, though I'm not sure what the best software or website would be to get him started

* His parents were also thinking about getting him involved with "Mathletics" ( http://www.mathletics.co.nz/ ) although I don't know anything about it.

I was hoping I could tap into the vast pool of amazing knowledge that is the Hacker News community. Any other ideas, recommendations, or advice?

Note that he's an avid soccer player and his dad (a photographer, film set designer, guitar player, skateboard maker, and builder) has the artistic and hands-on angles covered, so if you feel like giving advice along the lines of "there's more to life than maths" please refrain from doing so -- this question is specifically about cultivating his skills relating to maths and logic.

Many thanks in advance!