I found some simple SDL examples that compile for Maemo here:

https://garage.maemo.org/projects/n770demos/

For future reference (mine, or whoever), this is how I built the n770-fire demo under the scratchbox:

gcc -o n770-fire n770-fire.c `pkg-config --cflags gtk+-2.0 hildon-libs` `sdl-config --cflags` -ansi -Wall `pkg-config --libs gtk+-2.0 hildon-libs` `sdl-config --libs`

After using sb-menu to switch to the ARM environment, compiling, I was able to transfer and run the executable from Xterm on the N800!