Expanding a bit on my gamerscore challenge experience, I thought it might be interesting to mention how my kids reacted to some of the games that were played. I admit, more than one game was aimed at kids. Achievements for kids' games tend to be easier to get, so for a challenge, they're ripe for the picking.
As I mentioned, my oldest son just happened to rent Open Season just as the challenge started. What did an 8-year-old boy think of this game? Honestly, he didn't seem to like it very much. He played it the first night, but on the second day, he really wasn't that interested in playing, even when we warned him that, as a rental, the game wouldn't be with us for very long. The following day was a weekend, and he did play a little more then, especially when he found out that the little treasure gems unlocked facts. Being a little know-it-all, he's very into facts with which he can show off later.
He seemed to have a little more fun with TMNT. Its game mechanics are really simple and easy to pick up, and the game has a lot of action. My second-oldest, who isn't as big a gamer as his big brother, liked to watch his brother play this one. I don't recall him getting very far in it, but he did have fun with it.
My son likes playing EA's NBA 2002, the last basketball game I purchased (and still playable, thanks to backwards compatibility), so I figured besides the easy points, NBA 2k6 would be an appreciated upgrade. The first game we played together was full of frustration — despite the fact that we were playing a team whose every player's stats grossly outranked every player on the computer's team, we'd miss wide-open shots the computer would make under pressure, easily. He complained the whole game (as he's wont to do) how he'd rather play the old one.
Then I introduced him to the sliders. We pulled the computer's abilities down to about ¼ and put ours up to about ¾, and suddenly it was the Harlem Globetrotters against the Washington Generals. I forget the final score, but it was well over 200 to zero. He (and I) had a lot more fun then. :D
Finally, the kids played a bit of Avatar. Turns out there is more to the game than the first five minutes. ;) After the whole family took turns milking the game's easy points (even my wife, boosting her score from a mere 40 to a whopping 1040), the kids decided to play the game the way it was really meant to be played. I guess you might cast it as an action/platformer, along the lines of the first three Harry Potter games — sometimes you're fighting bad guys, sometimes you're pushing giant blocks around to climb up on, sometimes you're just running through dungeons blasting giant rats. Occasionally they had a little bit of trouble trying to decide where to go next, but all in all it didn't seem too hard for them to pick up. It's pretty simple, with cutscenes that are fairly reminiscent of the cartoon show (or what little I remember of it — we don't watch a whole lot of TV around here as a habit).
If I had to rank the games, I'd say Open Season was probably dead last. TMNT and Avatar would be in the middle, although I'm not sure in what order — the turtles seemed to be on a slightly older level than he might be ready for, and I can attest to the game getting a lot harder, especially in the boss battles; whereas Avatar was definitely set up to be more of a cartoon feel, and they definitely liked that. NBA 2k6 is a little higher up there, as long as the settings are modified appropriately.
The real winner is one game that I haven't mentioned at all yet: Samurai Warriors 2. On the last night of the challenge, I called up local Geezer FireMedic41 to see if he had any games with easy achievements, and he loaned me that one. I didn't mention it because, although the achievements are fairly easy, they take a lot of time. After I played NBA 2k6, I started playing Samurai Warriors 2 to fill out the rest of the time (until I discovered that I needed to play Avatar), and I got about two-thirds through one story, which would've earned me one 50-point achievement. I'm still plunking away at it, because I'm a certified achievement whore, but it should be noted that my kids have played it just about every day that they've played any games at all. They have been loving the hack 'n' slash gameplay, even if they don't have a full grasp of the objectives.
So there you have it. Open Season, definitely bad; Samurai Warriors 2, definitely good.