Explorer hack:
Make Win98 SE Explorer have more columns for things like Created date and Last Accessed date. Currently, Modified date is the only one of the three possible date columns that is employed. There is already a registry hack for Attributes, but a hack involving what I'm mentioning would require a reworked core file, I believe.
Later versions of Windows have this capability in Explorer, just not Win98 SE.
Don't know about WinME having this capability.
