[Someone want to either point to a Tcl/Tk script only example of display data graphically, or provide an example here? This page has been a junk page for a couple of months now. ]
Certainly there are extensions like BLT that provide wonderful graphing capabilities. But if someone just wants something simple...]
Related pages on the wiki:
Try looking at some of the Tk demos; drawing a graph isn't hard. What's hard though is working out what kind of graph to draw.
Check out the graphics category for other possible leads.