Nope, I don't get any numbers/labels either.
Seems like the website is incompatible with a bunch of browsers.
If not, what browser are you using? It would be nice to know if Flot is not compatible with something.
I also tried Konqueror Version 4.8.4 (KDE's browser) and it didn't even display the graphs (not in the blog post or on flotcharts.org).