Updated.
You can now press [WINDOW] to alter the 'rules' of the game.
The original game of life turns cells on if they have 3 neighbors, and lets them survive with two or three - now you can alter these rules for interesting simulations.
The skulls mean that the cell dies, the blank allows survival, and smileys let cells be born.
For particularly interesting configurations, check this:
http://en.wikipedia.org/wiki/Life-like_cellular_automata.
For now, not all of the configurations will work, (in the cases where its possible for a cell to be born, but not to survive with the same amount of neighbors), but the majority do.
Also, press [ZOOM] to try toggling between full speed mode (only on the TI-84+SE, I think) and normal.
Pressing [DEL] will clear the screen while editing.