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. TicTacToe
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.
