Is it possible to add block to the on-brick "NXT Program" menu? I have an NXT 2.0 (8547) set.

Is it possible to add some custom blocks to the NXT progranm submenu on the brick itself (like the existing "forward 5", "turn left", ...) so that I can add and use some simple steps there without the use of a PC?

Rationale: I'm playing around with the block with my small daughter (3), and adding in the PC to do something isn't very small-children friendly :-)
There is a piece of software called ICON (archived copy) which runs on the NXT and allows you to create programs on the NXT with many more commands than the built-in NXT programmer.