Given the high ratio of thinkers to members on the C&F, I feel the following will likely be appreciated…
the Futility Closet
http://www.futilitycloset.com/
From the aforementioned site:
You’re in a rowbat in a swimming pool, and you’re holding a cannonball. If you throw the ball into the pool, will the water level rise or fall?
I couldn’t wait for the answer. So I answered it. Highlight below to see my answer, and explanation:
[Begin Highlight]
The water level in the pool will fall.
This seems counterintuitive, but the reason is that the water level will change by the displaced volume of the objects in it, not their weight. However, the weight of the cannonball will cause the boat to displace more water than the cannonball itself. Therefore, tossing the cannonball overboard will cause the boat to to displace less water, and must surely cause the water level in the pool to fall, though perhaps almost imperceptibly.
[End Highlight]
Am I right?
I agree with you, fyffer. Although the way my back is feeling today, I am glad it is not me who is throwing the cannonball.
I’m inclined to believe that answer, fyffer, and in total agreement with Doug as well. 
In the chess problem, white has 29 legal moves, and what they all have in common is that all of them checkmate black, the opponent. But we could have guessed that, since these problems are on futility closet.
I’m getting an empty page at that URL. Is that supposed to be the “futility” part?
djm
I can’t connect to them anymore.
Surely, C&F can’t singlehandedly bring down a server?!
I mean, we’re not slashdot, FCOL!
So, futilitycloset.com has been Chiffed!
The site’s back.
This entry is stupid:
There’s no record that Jesus went potty either, but I’m pretty sure he did.
Well, ya never know… perhaps perpetual constipation is a prerequisite for performing miracles. 
… will the water level rise or fall?
The water level on the side of the pool, or the side of the boat?
The boat will float a touch higher. The pool will show no effect.
Well, it worked for Martin Luther.
djm
Thanks for the link. It really is interesting stuff.
And, this:
Squares A and B are the same shade of grey. I NEVER would have believed it. You have to put a very small hole in a piece of paper and block out the surrounding squares to really be able to see it. That’s the most effective optical illusion I’ve ever (mis)seen.
Dale
I know! I know that it is true, but I just can’t get my brain to believe it until I crop a copy of the photo and poition it over the original… it is indeed the same color/tone/hue. It just boggles my poor little mind.
I wasn’t fully convinced until I loaded it into PhotoShop an cropped a swatch out of A and another out of B and then put them side by side on a white background. Then they look ALMOST the same, but the different shadings of the letters A and B throw the eye off slightly. When you smudge those away, the two shades are shown to be dead identical.
One of my interests in the last few years has been the profound psychological shaping of human perception and memory. (For me, this has a criminal justice implication that I’m interested in.) An optical illusion is a very different process from the kind of psychological distortions I’m talking about, but, it’s still as good of an illustration I’ve ever seen about how a person can be SURE they see something a certain way and it’s just not so.
I think think it should be written that letters A and B are the same shade; the square are certainly lighter/darker or did I just screw up??
The squares are actually the same color. The letters are not.
My eyes and brain just can’t cope with seeing them as the same, even after I’ve proven it to myself.