I've seen videos like this one in which a effect appears when the user made a click. What I want it's just the effect only, I don't care the colour of the cursor.
How can I make this effect when I do a click in Ubuntu 11.10?
As indicated in this very similar question, your best option appears to be using keymon; it is fairly easy to customize it for an effect similar to what you see in your video.
From the Software Center, or via sudo apt-get install key-mon
The default window shows mouse and keyboard status, like:
Unless you want it, let's get rid of all these; right-click on it window, and chose Settings:. Then, uncheck everything under Buttons:
and set up the Misc tab as:
This leaves you with a minimal status window:
And the default click-indicator, which you don't like very much :)
First, let's make the keymon window disappear. Simply run it from the terminal (you can set up a launcher, script or startup too) as:
key-mon --scale=0.1
Next, the files we need to modify are in /usr/shared/pyshared/keymon, so cd to that folder.
Make the click-indicator bolder: in shaped_window.py, find win.set_opacity(0.5) around line 58 and change the 0.5 to 1.0
Increase the fade-out time: at the end of shaped_window.py, find gobject.timeout_add(200, self.hide) and change the 200 to e.g. 750 (it's in milliseconds)
Change the indicator: The indicators are simply SVG files, under themes/*/mouse-indicator.svg; you can edit these with Inkscape, etc. to customize it to whatever you want to be.
sudo wget http://pastebin.com/raw.php?i=rBnUiXWh -O/usr/share/pyshared/keymon/themes/classic/mouse-indicator.svg
Now start keymon, and you'll see a nice red fading-out indicator like the one in your video around the cursor whenever you click/drag:
