I wonder if it is possible to make Nautilus grouping files and folders as Windows do. This is the only thing I don't like in Ubuntu interface. In Windows in every folder my files are always separated to last edited groups: today, yesterday, this week etc. In Ubuntu, say, in Downloads, I hardly able to find what was downloaded 5 seconds ago. Any tweaks/software to implement this? I'm using 10.10.
This is exactly what the Zeitgeist project aims to provide users with. You can download and get the latest version of Zeitgeist and the browser which will not only show you what you last worked on / downloaded but lots of other cool stuff.
Zeigeist is being worked into the unity interface for 11.04 in the places menu, so you'll only need to go there to see recent downloads sorted by date and categorised by time period.
As Martin Owens has said, Zeitgeist is a new technology to implement this kind of functionality. It is integrated into the Unity file browser but as far as I know, there is no way currently to add this functionality to Nautilus. However, there is a graphical front end to Zeitgeist called GNOME Activity Journal which may be of use to you. It provides chronological access to your files. It also has search and contextual grouping of files.
sudo apt-get install gnome-activity-journal
This may not be an exact answer. But for grouping files and folders like windows explorer, you can use Dolphin. To install dolphin type
"sudo apt-get install dolphin"
in terminal. From menu bar->view->show in groups