"Linux only: It's still a work in progress, but GNOME Activity
Journal already offers a nice at-a-glance look at your file work
over the last few days, offering usage charts, image previews, and
quick file access.
"At the moment, GNOME Activity Journal can't do much more than
present a nicer face for your system logs, and show what local
files you opened, modified, or saved. It shows the order in which
you worked on your files, lets you "pin" certain needed files to
that day, and, well, that's about it for now. Still, that's a lot
more helpful than digging blindly through your recent documents
list, and way easier than running regular expression searches on
your system text logs.
"GNOME Activity Journal is a free download for Linux systems. If
you need help installing it in Ubuntu, the Web Upd8 blog has a
handy little how-to on that."