"All ages can get into it."

How challenging is it to complete? Im an 26 y/o engineer, am I going to be done with this thing in 20 min.?

I got one of these years ago as a gift and love it. It gets progressively harder as you go along and is tied to your dexterity, so generally people never make it much past the point where they failed on the first go.

My one complaint is that if you have it on a shelf and accidentally bump it, the little metal ball will roll back and forth inside for a good 15 minutes making an annoying sound.

I immediately went off to order one for my nephew. But oops, I entered my own shipping address. ;)

Maybe I will get him one, too. But I have to test it, you know. Yeah, that's the ticket, I have to test it first.

The inventor has built larger versions for museums (3-4ft in diameter). There's an article about him in MAKE: Magazine, vol 20, p40-45 (I think this is still the current issue, but I don't know when the next one comes out).

I almost bought one of these for a Christmas gift, but I wasn't sure if it would be cool or lame. So, thanks for the recommendation-- it's going on the list for next year!

I received one of these for Christmas and everyone who has seen it has considered addicting.

@ Robert It's not really intellectually challenging, but more of a dexterity/3D thinking challenge. Unless you are fantastic control of your fine motor movements, it will take at LEAST a week.

@Mike In the version that I have, which looks identical to the linked video, there is a "storage hole" to the right of to the three start ramps. If the ball is in there, as long the toy doesn't roll on your shelf it shouldn't make that noise.

Please list other vendors besides Amazon.com. I went to the maker's website and here are other online stores that aren't the megastore that Amazon is:
ThinkGeek.com
Toysgamespuzzles.com
Game Daze
New Horizon Toys
Toys Camp
Creative Kidstuff
Educational Kids Play
PLEASE SUPPORT ONLINE VENDORS THAT ARE NOT AMAZON! AND PLEASE OFFER YOUR READERS OPTIONS WITH OTHER ITEMS TOO. AMAZON IS NOT THE ANSWER TO EVERYTHING. THEY ARE LIKE WALMART, BUT ONLINE.

Although I am a bit of an Amazon addict, and although KK makes a little bit from each purchase at Amazon, I'd like to echo the message of the last comment, without resorting to caps: please try to support some of the smaller retailers when price and convenience allow. There's good reason to do so. Walmart : small town merchants = Amazon : small web retailers. (More links to small retailers would be appreciated.)

@Mollie: We list products with Amazon if they have the best or comparable price. And usually they do. If we see another source with much better prices, we will list that, or if it is not available on Amazon. It is very rare when Amazon is the ONLY place something is available. And we also try to list the source (as we did with Perplexus) so you can either get it directly from them, or see what your other options are.

We list in Amazon first for several reasons:

1) As I mention, Amazon usually has the best price. This is a reader-oriented site. We are not trying to please advertisers first, or sponsors, or the vendors of products. Vendors ask us to do many things for them, which we don't do (they'll want *their* link rather than someone elses). Instead we are always focused on readers. So we'll try to find the best place to buy for users.

2) The work of Cool Tools is supported by the affiliate program at Amazon. When you buy something from an Amazon link on this site, we get a small percentage of that purchase, and other purchases on that visit. That income pays for our servers, programmers, and the editors (not me) who produce one new review per weekday.

3) But the most important reason we generally list Amazon is because they are the most reliable and convenient. Whenever we list a small-time source we are taking a chance that their delivery will not be reliable, or their return policy not good, or their shipping charges excessive, or spam policy stupid, or whatever. Sadly, we've guessed wrong on a number of products in the past, where we had to pick a small vendor with no experience, only to hear from readers that that source was not reliable. In the spirit of Cool Tools where are written by people who have actually used things, we like to provide sources that we have actually used. Amazon is not the only source we have used, but combined with the reasons above, we have generally found it to be the most reliable for most users.

4) I personally find the other users reviews on Amazon to be very helpful, and often more numerous than on other sites (if they have any reviews at all), and therefore there is yet another bonus to having that link first. (I realize there is a feedback loop wherein the more folks that use Amazon, the more attractive it becomes. That's the new economy.)

5) Finally, these days it is so easy to Google, or use Google Product, or Find!, or hundreds of other shopping comparison sites to find alternative online sources for things that you don't need us to list them. We simply can't do as good a job in finding them as they do.

To sum up, we list Amazon because it is a convenience for most readers. Think of it as the place to start looking. You can see what a good price is that you should expect to pay, you can read the reviews, you can see the specs all laid out, you can see similar products. If all those meet your approval you can buy in one-click. If you care to patronize alternative sources, you are now better informed to do so.

In my experience this is how most people shop already. It's rare someone buys something from another source without first checking on Amazon just to get a baseline. We provide the link for that baseline.