Getting multimedia to work
The default Ubuntu install contains free software only,
which means that it doesn’t support some popular multimedia formats
straight out of the box. This is inconvenient, but the Ubuntu folks
have good reasons for not shipping with support for MP3, DVDs, and so
forth — including that software could cause them some legal headaches,
or incur some serious fees.
Fortunately, as a user, you don’t need to worry about fees (though
some of the packages may not be legal due to patent restrictions or
restrictions on circumventing copy protection, depending on where you
live). The Ubuntu wiki has a page on restricted formats
that explains how to get the packages you need. However, if you run
Ubuntu on AMD64 or PowerPC hardware, you’ll still be out in the cold
for some of the packages, since some multimedia formats depend on
proprietary software that’s not available for those hardware platforms.