Real Time
You can update a chart periodically to get a real-time effect by using a timer to insert the new data in the plot and redraw it.

Time between updates: milliseconds

Multiple axes
As illustrated, you can put in multiple axes if you need to.
The plot command returns a plot object you can use to control the selection

You selected:

Selections are really useful for zooming. Just replot the chart with min and max values for the axes set to the values in the "plotselected" event triggered. Enable the checkbox below and select a region again.

With the stack plugin, you can have Flot stack the series.

This is useful if you wish to display both a total and the constituents it is made of. The only requirement is that you provide the input sorted on x.