I saw YourFonts over at Cool Tools the other day and immediately thought about the applications for gaming. This is a free font generation software package. You download a template and either draw/write the font by hand or create it in an image editor. Scan and upload the template and it gets turned into a TrueType font. How is this useful? Do you have a runic or script alphabet that you use in your game? Make a font out of it. Do you have icons that you'd like to be able to add to a character sheet and your GM notes (like the 4e dice and attack icons and such)? You can create your own dingbat-style font full of them. Do you want to create some sort of arcane glyphs or code-symbols that show up repeatedly through a campaign? This is your tool.
I haven't played with it yet, but I plan to do so. If you try it out, let me know what you think - and what you use it for.