From Michael Nahrath:
JavaVis is a small Java program that graphs the contents of a distributed.net client's log file.
To use it just launch the program and go to the File menu to open a log file or drag&drop a logfile to the progam icon. Up to 4 recent logfiles will be remembered in the file menu.
Zooming in is accomplished by drag-selecting part of the graph with your mouse. To zoom out, control-click on the graph and choose 'complete' from the one-item popup menu.