I’ve found here loads of fonts which can be easily and freely installed on Ubuntu.
If you want to have the fonts showed in the picture (and many others), you only have to run:
$ sudo apt-get install ttf-dustin
For more fonts, visit the link above (and don’t forget to glance at the comments, there are many other interesting resources).
PS: of course, the fonts can be used in other distributions apart from Ubuntu, but the names of the packages and examples of the commands are shown taking this distro in mind.