The latest MacOS release (10.6, or "Snow Leopard") comes with a new monospace font. It's called "Menlo" and it's a slightly modified form of the standard Linux font (with appropriately weightly Linux name) "DejaVu Sans Serif Mono", which is itself an updated form of Bitstream Vera Sans Mono. Apple's modifications are a definite improvement to my eyes, mostly because they thicken up some of the wispier glyphs from DejaVu, like the underline and period. There's a great comparison over here.
One thing that bothered me, though, is that they turned the zero into a 1980s-style "slashed circle". Unhip, daddy-o! Naturally I searched for a font editor, and the best one I found was Font Forge, an old Linux app ported to the Mac but still requiring X11. So that's two ways OS X is borrowing from Linux for font support. What's up with that? Was there an elite cadre of fontistas working on Linux machines in a secret bunker? Linux is, um, not usually known for its great designers.
I couldn't limit my tweaking to the zero glyph, so in the end I made about a dozen changes. Bitstream released these fonts with a very open license that only requires that you change the name if you change anything about the font, so I'm releasing my changes with the same license, as the font "Mensch".
Read more: robey