master.xml

<data>
	<current-game-rules>
		<section id="9" handle="rules">Rules</section>
		<entry id="12">
			<rule-brief handle="eat-a-serving-of-fruits-or-veggies">Eat fruits or veggies</rule-brief>
			<points handle="1">1</points>
			<game-link>
				<item id="9" handle="2013-01-12-19-04-00" section-handle="games" section-name="Games">2013-01-12 19:04:00</item>
			</game-link>
			<date-created iso="2013-01-12T19:07:00-06:00" time="19:07" weekday="6" offset="-0600">2013-01-12</date-created>
		</entry>
		<entry id="11">
			<rule-brief handle="exercise-for-30-minutes">Exercise</rule-brief>
			<points handle="2">2</points>
			<game-link>
				<item id="9" handle="2013-01-12-19-04-00" section-handle="games" section-name="Games">2013-01-12 19:04:00</item>
			</game-link>
			<date-created iso="2013-01-12T19:06:00-06:00" time="19:06" weekday="6" offset="-0600">2013-01-12</date-created>
		</entry>
	</current-game-rules>
	<member-activity>
		<section id="10" handle="activity">Activity</section>
		<entry id="84">
			<member-link>
				<item id="7" handle="jesse" section-handle="members" section-name="Members">Jesse</item>
			</member-link>
			<game-link>
				<item id="9" handle="2013-01-12-19-04-00" section-handle="games" section-name="Games">2013-01-12 19:04:00</item>
			</game-link>
			<rule-link>
				<item id="12" handle="eat-a-serving-of-fruits-or-veggies" section-handle="rules" section-name="Rules">Eat a serving of fruits or veggies</item>
			</rule-link>
			<date-created iso="2013-01-16T00:00:00-06:00" time="00:00" weekday="3" offset="-0600">2013-01-16</date-created>
		</entry>
		<entry id="81">
			<member-link>
				<item id="7" handle="jesse" section-handle="members" section-name="Members">Jesse</item>
			</member-link>
			<game-link>
				<item id="9" handle="2013-01-12-19-04-00" section-handle="games" section-name="Games">2013-01-12 19:04:00</item>
			</game-link>
			<rule-link>
				<item id="11" handle="exercise-for-30-minutes" section-handle="rules" section-name="Rules">Exercise for 30 minutes</item>
			</rule-link>
			<date-created iso="2013-01-16T00:00:00-06:00" time="00:00" weekday="3" offset="-0600">2013-01-16</date-created>
		</entry>
		<entry id="79">
			<member-link>
				<item id="7" handle="jesse" section-handle="members" section-name="Members">Jesse</item>
			</member-link>
			<game-link>
				<item id="9" handle="2013-01-12-19-04-00" section-handle="games" section-name="Games">2013-01-12 19:04:00</item>
			</game-link>
			<rule-link>
				<item id="12" handle="eat-a-serving-of-fruits-or-veggies" section-handle="rules" section-name="Rules">Eat a serving of fruits or veggies</item>
			</rule-link>
			<date-created iso="2013-01-16T00:00:00-06:00" time="00:00" weekday="3" offset="-0600">2013-01-16</date-created>
		</entry>
	</member-activity>
</data>

master.xsl

<xsl:stylesheet version="1.0"
		xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
		xmlns:exsl="http://exslt.org/common"
		exclude-result-prefixes="exsl">
                  
  <xsl:output method="xml" indent="yes" />

  <xsl:template match="/data">
    
    <!-- Get points for each activity -->
    <xsl:variable name="points-per-activity">
      <xsl:for-each select="member-activity/entry">
        <points>
          <xsl:value-of select="/data/current-game-rules/entry[@id = current()/rule-link/item/@id]/points"/>
        </points>
      </xsl:for-each>
    </xsl:variable>
    
    <xsl:text>Total Score: </xsl:text>
    
    <!-- Use sum() function to find the total -->
    <xsl:value-of select="sum(exsl:node-set($points-per-activity)/points)"/>
  </xsl:template>

</xsl:stylesheet>