Stephen Gould

Eggs and Floors
You need to figure out how high an egg can fall from a 100 story building without breaking. The eggs might break after being dropped from the first floor, or might survive a drop from the 100th floor. You have no a priori information. You have two eggs. What is most efficient way to drop the eggs so that no matter which floor they break on, you will always be guaranteed the minimum number of drops? You are allowed to break both eggs, as long as you identify the correct floor afterwards.

What if the building was N stories high?

Orange Juice
You have a glass of water and a glass of orange juice. The volumes are identical. You take a teaspoon, put it in the glass of juice, take a full spoon and put it in the water. After stirring, you take a full teaspoon of the mixture back into the glass of juice. Which amount is greater: the amount of juice in water or the amount of water in the juice?

Sudoku
Sudoku is a simple numbers game that has become very popular with newspapers lately. The objective is to fill the puzzle so that every row, every column, and every 3-by-3 submatrix contains the digits 1 to 9, with no number repeated. The puzzle is essenitally a constraint satifcation problem, and here's an applet I wrote for solving it - you can type in your own numbers by clicking on each cell. Contact me if you'd like the source code.

JRE 1.5.0 required