Many fonts are packaged for Ubuntu and available via the "Fonts" category of the Ubuntu Software Center. If you prefer apt-get, search for packages starting with otf- or ttf-.
You can also double-click on the font file (or select Open with Font Viewer in the right-click menu). Then click the Install Font button.
If you need the fonts to be available system-wide, you'll need to copy them to:
/usr/local/share/fonts and reboot, or manually rebuild the font cache with:
fc-cache -f -vYou can confirm they are installed correctly by running:
fc-list | grep "<name-of-font>"You may need to restart some programs, like OpenOffice Writer, before they actually show the new fonts (usually such programs are caching the font list when they start up).
Once your desired fonts are installed, see the "Change system font" article.