A while ago I made a sparkline font at the khan academy when i was working with david hu on creating more forgiving streak bars. Instead of writing some obtuse homebrew canvas script that would be hard to maintain i thought: why not use a font to represent the same thing? The text then, could be meaningful, and you'd have the advantage that the sparkline display would gracefully degrade.
We tried it out and the project went another way, but the font remained in its pre-v1 stage. It's not such a terrible idea but it could use some more work (i.e. the comma could be a zero-width character to make rerendered chartjunk legible again). Please edit, hack, update, do whatever (but please, only for good, never evil).
In this project, i'm providing it both as a css base64 encoded font (for webpages), as a UFO file and also as an OTF. I don't have any current intent to support this at the moment, but sparklines are always interesting and having tools available for implementing them is always nice.
There are probably other tools that do this better, so you're probably better off using those, but if you like this, then hooray!
license JSON for the js, OFL for the font.