1. Knights and servants

There are 3 couples of knights with their servants, on the left bank of a river, in front of a boat that can carry only two persons.

The knights are blood thirsty and will kill a servant if he remains unattended.

Can you help them pass the river with no servant been killed?

And if you succeed with two or three couples, can you do it with four or five couples?

2. Cat (...stuck on math) and mice

Around a cat there are N mice, one of which is playful. The cat must eat all N mice.

When the cat eats the playful mouse, he stops eating mice.

But the cat is stuck on math and he eats mice following the pattern: after he has eaten a mouse, he does not eat the next mouse at random, but he eats the one that will stop after counting N mice in a raw. The cat counts always in a counterclockwise direction.

Click on the mouse that you think the cat should start eating from, such that the last mouse to be eaten is the playful one.

If you think it is easy for 3 mice, then try it for 13.

3. Order the tiles

On a 4x4 grid there are 15 tiles and one empty cell. A number is written on each tile. By moving the tiles around you have to put the numbers in order.

You can solve the game always, if the number 14 appears twice. But is this true when all the tiles have different numbers?

4. Tic-Tac-Toe

Try to win by playing against the smart computer.

Finally, when you realize that you will never win, switch to playing against the novice computer or your little brother.

5. Physics Hall of Fame

40 portraits of scientists (extracted from Wikipedia) influential mostly to evolution of physics must be named.

When a scientist is correctly recognized then by clicking on his portrait you can connect to the corresponding Wikipedia entry.

The activity is timed.

6. Repelling numbers

Place the numbers from 1 to 8 or from 1 to 12 in a way that two nearest neighbors cells do not contain consecutive numbers. Nearest neighbors cells have either a common side or a common vertex.