Good logic puzzles:

You are standing outside a closed door. On the other side of the door is a room that has three light bulbs in it.
The room is completely sealed off from the outside. It has no windows and nothing can get in or out except through
the door. On the outside of the room there are three light switches that control each of the respective light bulbs
on the other side of the door.

Your assignment is to determine which light switch controls which light bulb. You are allowed to enter the room only
once, and once you come out, you must be able to state with 100% certainty which light switch controls which light bulb.

A:  Flip the first light switch. Leave it on for 10 minutes. Turn it off. Flip the second light switch. Walk into the room.
The light that is on is connected to the second switch. The light that is off and cool is connected to the third light switch.
The light that is off and warm is connected to the first light switch.

* * * * * * * *

You have Some Terminal Condition, which necessitates taking two pills a day: one Pill A and one Pill B. If you neglect
to take either pill, you die; if you take more than one A or more than one B, you die. If you don't take them at exactly
the same time, you die.

This morning you are going through your usual routine. You pick up your bottle of A Pills and gently tap one into your palm.
Then you pick up your bottle of B Pills and tap it, but two pills accidentally fall into your hand. You now hold three pills
(one A and two Bs), you don't know which are which, and they are completely indistinguishable from each other. The A Pills
are the same color as the B Pills, they are the same shape, same size -- they appear identical in every respect. Man, your
doctor is a dumbass. But he's a rich dumbass, because he's charging you $10,000,000 a pill! So you dare not throw any away.

Thus, the puzzle: what can you do to ensure that you take only one A Pill and only one B Pill today, without wasting any pills
(either today or in the future)?

A: add one more A pill to the mix. Then cut them all in half and eat half of each pill today. take the other halves tomorrow.

* * * * * * * *

A bad guy has kidnapped 4 people. He brings them to a wall. He instructs one person to stand on one side of the wall, and the
other three to stand on the other side of the wall. They are instructed to stand in a single file and face the wall like so
(<- indicates a person and the direction they're facing, | the wall):

-> | <- <- <-

The wall is not see through and each person can only see what or who is in front of them, except the captive in the back of the
line of three, who can see both captives in front of him.

The bad guy has 4 hats, two white ones and two black ones. He puts one hat on each person. Each captive cannot see what hat he
or she is wearing, but can see the hat of whatever captive (s) he or she can see.

The bad guy then declares to the captives: "I have placed on your head either a white hat or a black hat. In total there are
two white hats and two black hats. If one of you can identify with 100% certainty what color hat you are wearing, you can all go
free. If you are uncertain or guess, you will all die, whether you are correct or not."

After some time, one captive correctly declares with 100% certainty what hat he or she is wearing and the captives go free.

How was he able to determine this? 

A: If the guy at the back of the three person train sees two hats of the same color in front of him, he can easily assume his
own hat color, since the kidnapper tells them there are only two of each. If both of the people in front of him are wearing white,
he can only be wearing black. If the two are mix-matched, then the guy in the back won't say anything. But, the guy in the middle
will notice that the guy in the back won't say anything. So, the guy in the middle knows that the hats are mismatched, and thus,
the hat in front of him is opposite of his own.

* * * * * * * *

Four ships are sailing along, each an equal distance from the other three. One is a steamship, one is a sailing ship, and one is a
trireme (ship with oars.) What kind of ship is the fourth one?

A: airship (4 at equal distance = tetrahedron)

* * * * * * * *

There are three jars labeled on a desk. One is labeled "Black Beans", one is labeled "White Beans" and one is labeled "Black and
White Beans". Unfortunately, you used some crappy glue, and the labels fell off. You went to the store, bought some better quality
glue, but when you re-attached the labels, you put them all on the wrong jars.

You can open a jar, pull out a bean, and put it back. How many times will you have to do this until you know what each jar contains?

A:   1 bean. You pull from the one labeled Black and White. If it's White, then you know it is the all white one, because it is
mislabeled. It also means the one labeled "All Black" must be Black and White, because it is mislabeled so it isn't all black and
can't be the "All White" one because you know where that is now. Once you have two, the third is easy. The answer is pretty much the
same if you pull the black bean from the mixed container.