Sort-of gaming related question

[dogknob]

I grabbed my landlady's 1-year old computer, which had been gathering cobwebs after she caught some sort of bug that slowed it down to an unusable pace.

I wiped everything off of it. I mean I nuked it. I booted from an external Linux disk and wrote zeros over the entire computer. Took about 5 hours.

Then I installed Ubuntu Linux and gave the computer to my 66-year-old history-buff roommate, who has never used a computer in his entire life. We're talking starting-from-the-absolute-beginning, intimidated-by-mice newbie.

I figure he'll get good enough on the thing to be able to supplement his reading (mostly historical fiction and non-fiction) with online info; it would be great if he got into that instead of watching Bill O'Reilly every day at 5. I can only hope.

I remembered that I pretty much learned how to use a computer by playing games, but solitaire and pinball isn't going to interest this guy.

Can anyone suggest some easy-to-learn, engaging games for Linux? I've looked at Freeciv and Battle for Wesnoth and I am installing both...

Any other suggestions?