CSS Weekly Bar Charts
Demo Version
Here's a vertical bar graph showing a hypothetical set of weekly data to count steps. It's based on CSS created by Eric Meyer: CSS Vertical Bar Graphs
The bubble tooltips are not ideal, since they are using a CSS background PNG image with a fixed width and transparency. This will cause some issues in IE6.
This version adds a z-index to the bar class to keep the bars from overlapping the bubble tooltips. It also specifies a position of top: -78px instead of bottom: 104px. This keeps the bubble hovering right over the bar.