The Letter Spirit project is a cognitive science project that models creativity in typeface design. The project involves the design of a gridfont; that is, a font constrained to a 2 by 6 grid.
The applet below is intended to help with the design of gridfonts.
Clicking on any of the grid stems will toggle it between on and off; if the position that you click on is near to more than one grid stem, then they will all be toggled.
You can also load and save a description of the gridfont in a text based format. Since this is an applet, it can't read from or write to your hard disk so you'll have to copy the text to and from an editor.
Finally, you may also be able to download from the server one of the existing fonts that other people have designed (note that whether this is available depends on your local security settings, and also the download may take a little while).
I have also got a template for displaying a complete grid font as an encapsulated PostScript file. To use it, you'll need to edit the file and replace the name and individual letter encodings with those for your particular font.