An implementation of Conway's Game of Life for J2ME MIDP 1.0 devices (most newer cellphones, palm,...). The Game of Life is a fun example of cellular automata. Starting with a grid of cells, each of which is either alive or dead, the game evolves according to a number of simple
rules:
If a live cell has less then two live neighbours, it will die out of loneliness.
If a live cell has more then three live neighbours, it will die due to overcrowding.
If an dead cell has three live neighbours, reproduction causes it to become alive.
Otherwise (two live neighbours), the cell will stay the same.
The Game of Life is interesting, because it shows how rather complex patterns
and behaviour can emerge from a very simple set of rules. This is called
'emergent complexity' and also applied to studying e.g. plants in nature itself.
Finally, the game of life could, with a large cell grid, be used as a computer, even though this would be rather impractical of course. This is done by e.g. modelling computations as interactions between certain patterns.
There's a lot of information to be found about the Game of Life. There is a nice book called 'The Computational Beauty of Nature' by Gary William Flake, which
describes it along with a lot of other stuff. There are also some nice
articles about it.
Unfortunately your cellphone will not be as fast as your computer, however, try some patterns in the bus when you're bored :)