Original version, based on Joe Gregorio's Python version, in C# as an HTTPHandler for ASP.NET.
Version 2.1, added normal ranges, per Edward Tuft's improvements.
Version 2.2, added GIF transparency support.
Version 2.3, added data scaling functionality for reader Matt.
The latest source code.
Joe Gregorio's sparklines, which got all this started.
A quick note regarding a mention of my sparklines handler in Scott Hanselman's HanselMinutes podcast and ASP.NET 2.0 MVP Hacks book.
Leveraging the transparent GIF-producing sparklines logic in a dynamic text image generator for ASP.NET.
Coolest use of my sparklines service: "...NBA team stats for every franchise-year from 1973-74 to 2004-05". Check out the 2005 season summary.