I've made a simple start at porting Debian's NetHack packages to Maemo 5 for the Nokia N900. For now there is just the console interface. It and the nethack-common package are now available in the extras-devel repository.
The packages are "optified" so they don't occupy space on the root partition.
Note that right now the default shell does not include /usr/games in
$PATH, so you'll need to either add that or just start it with
Bugs can be filed and files downloaded at the Garage project page.