Google Chart API looks quite useful. I've used Gruff to generate graphs before but this looks way easier (and much lighter on the server without all that ImageMagick magic!) I'll have to play with it someday - if only I didn't have to mess with those URL params!
sudo gem install gchartrb
Looking good so far and I dig the familiarity - Deepak says the API is Gruff-inspired and it tells. If you need a charting solution (for reporting or whatever), this is a gem to consider.
Ah yup, there'll be no Rails 2 feature today - just submitted a couple of Ruby 1.9 compatibility patches for Rails and feeling a little bummed out now (dependency handling is not that pleasant in Rails). Rails' Ruby 1.9 compatibility needs you!