LastActivityView is a tiny (99KB) tool which aims to show you exactly what's been happening recently on just about any PC (Windows 2000-8, both 32 and 64-bit editions).
The program can log the applications you've run, for instance. The files you've opened or saved. The folders you've viewed in Explorer. System startups and shutdowns, user logons and logoffs, restore points created, blue-screen crashes, restore point creations, Windows Installer actions, and more.
This has obvious technical support value. If someone asks you for help in diagnosing a computer problem, say, you won't have to rely on them remembering generally what they were doing on the system at the time. Just launch LastActivityView and you'll be able to see that they'd just ran this program, installed something else, and other relevant information.
And if you want to monitor the actions of your kids, employees or anyone else who uses a PC of yours, then the program could be an interesting option. No need to install an intrusive monitoring tool, LastActivityView provides a host of useful information on how a PC is being used just by retrieving information from the Registry, various file dates and so on.
The program has some limitations. It can only log files opened and saved in the standard Windows Open/ Save dialogs, for instance. System cleaning tools may wipe some of the information it uses, and the author warns that some action times can be incorrect if the user (or software) makes certain Registry changes.
Even with these issues, though, LastActivityView remains an excellent way to detail and log just what's happened on a PC over the past few hours and days.