I Also Know What You Did Last Summer (a.k.a. timeTracker)
"Tracks time you spent working on max files.
Update in v0.42: Fixed some bugs to allow timeTracker to run on more recent versions of 3ds Max.
Updates in v0.4b: Fixed some minor bugs. The small dialog is now dockable (idea by John Pruden). NOTE: version 0.4b only works with MAX 5. You can still download ver 0.31b from the links above.
NOTE: This is a beta version and should not be used in production.I would appreciate your feedback (and bug reports) in order to make this script stable and usable in production.