DocBook can also be used for question and answer sets:
<?xml version="1.0"?>
<!DOCTYPE qandaset PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
<qandaset>
<qandaentry>
<question><para>What is the answer to the ultimate question?</para></question>
<answer><para>42</para></answer>
</qandaentry>
<qandaentry>
<question><para>What kind of stylesheets are available?</para></question>
<answer><para>XSLT or DSSSL</para></answer>
</qandaentry>
</qandaset>