Solution to the Scale, Part 3 is up

I remembered the solution to the scale riddle with 12 weights and only 3 weigh-ins.  It's located in the expanded "The Scale, Part 3" post. 

The Scale, Part 3

Told to me by Tommy Dickie:


This time you have 12 identical-looking gold coins.  11 are equal weight, 1 is counterfeit and you don't know whether it's heavier or lighter than the others.  Using an old-fashioned balance scale only three (3) times, find the counterfeit coin and determine whether it is lighter or heavier than the others.  

The Monks

There are 40 monks living on a deserted island, at the foot of a mountain with a monastery at the top. Each monk has either blue or green eyes--there is at least one monk of each eye color, but none of them knows which color he has. They can see each other's eyes, but cannot in any way communicate to each other anyone's eye color (ie, everyone knows everyone ELSE's eye color, but not their own). They gather every day for supper, but otherwise spend their time alone in their individual secluded huts. One day, God appears and tells them all that green-eyed monks are welcome to hike up the mountain to the monastery; but ONLY green-eyed monks are allowed. He says that one morning, every green-eyed monk will wake up knowing that he is a green-eyed monk, and when that day comes, they will each ascend the mountain during sunrise, leaving just the blue-eyed monks to gather for supper later that day. This does indeed happen. How do the green-eyed monks accomplish this?

Sorry for the Delay

I'm sorry I didn't post anything last week. To compensate, I offer two riddles: one easy, one hard. I guess the easy one is whichever you get first. Feel free to post ideas in the comments section.

The first I got from Wu Riddles and the second from Tommy Dickie. The second is similar to a riddle about cheating husbands.

The Penny, the Cork, and the Bottle

Take a penny, an empty wine bottle, and a cork.  Put the penny in the wine bottle and cork the bottle.  Now remove the penny without pulling out the cork and without breaking the cork or bottle.

The Glass

You have a perfectly cylindrical glass completely full of water (no rounded edges on the bottom, same diameter all the way down).  How do you empty out exactly half of the water?  There are no markings on the glass and you have nothing else to work with.

2 Ant Riddles

1. An ant is on the corner of the floor of a perfectly cubic empty room and wants to get to the farthest corner of the room, on the ceiling.  What is the shortest route?
2. Four ants are on each corner of a square, 2x2" Post-It note.  Each ant is facing the ant immediately to his left.  All four ants begin marching at once, each aiming for the ant immediately to his left.  Eventually the four ants spiral into the middle of the Post-It note, where they meet.  How far does each ant travel?