It's amusing to see sparse trading all day, most volume coming on several big blocks, and then at the close, frantic activity as the longs push the price up and the market maker pushes it back to unchanged in a trade after 4:00.


http://bigcharts.marketwatch.com/quickchart/q...&show=

This is a dynamic chart so if you're looking at it Tuesday, it's the right-hand pane, but if you look at this Wednesday after the open, today will be the left pane.