Here's a fairly typical vertical bar graph showing a hypothetical set of quarterly data for, say, invoice and collection totals. The difference here is that the whole thing is a simple set of nested lists and CSS. Really.
The graph is a bit flat here because it refrains from using PNGs with full alpha channels to create fades on the graph background as well as the vertical bars. Try this visually nicer but much less IE/Win-friendly version, should you be so inclined.
Similar but much nicer-looking work was published in November 2005 by Apples to Oranges.