FF Chartwell, designed by Travis Kochel, is a typeface that represents sequences of numbers graphically.
Driven by the frustration of creating graphs within design applications (primarily Adobe Creative Suite) and inspired by typefaces such as FF Beowolf and FF PicLig, Travis saw an opportunity to take advantage of OpenType technology to simplify the process.
Before the True/OpenType era, Beowolf used postscript hacks to render slightly differently every time, creating a uniquely convincing aged effect; PicLig is a pixel font which uses OpenType ligatures to turn certain character pairs into useful symbols.
Chartwell is a more ambitious project than either, and comes in 7 different "weights", each producing a different kind of graph. $130 for the lot, they're $25 each if, say, you only like pies. A web version is under development.