Google released a seriously cool charting API today. The data and options about its presentation (not as many as IDL, but quite a few) are encoded into the URL of the image. Of course, there are plenty of chartjunk options, but it seems quite possible to make some serviceable graphs. The one thing I wasn’t able to was turn off the axes in order to make a sparkline. The charts shrinks to the right size , but I couldn’t remove the axes totally (nor make them transparent, set their color to the background color, etc.).
UPDATE: With help from Jonathan in the comments, I can now make a true sparkline . Also, check out Jonathan’s cool Google Charting Tool where you can easily create the line plot that you want.