The problem: to save valuable real estate on the tibook's keyboard, the page up and page down keys are shared by the up and down arrow keys. To page up or down, you have to hold down the function key with one hand and hit the arrow keys (on the opposite end of the keyboard) with the other--not very convenient when one hand is tied up holding a cup of coffee or the tibook itself.

The solution: that unused enter key and DoubleCommand. Using DoubleCommand, I remapped the enter key (located underneath the "." key, two keys to the right of the space bar and conveniently adjacent to the arrow keys) to turn it into another function key. Ah, now I can page down with my right hand as I read Google News while holding my maté gourd in my left hand.