Use the onRowClick JS function to modify the behavior's row click action. Here's a trivial example:

<apex:page controller="p1c">
<style>
.selectedDataRow {
    background-color: red;
}
</style>
<script>
function updateRowColor(row) {
    if(row.className.indexOf(' selectedDataRow') < 0) {
        row.className = row.className + ' selectedDataRow'
    } else {
        classes = row.className.split(' ')
        for(var x in classes) {
            if(classes[x] == 'selectedDataRow') {
                classes[x] = classes[0]
                classes.shift()
            }
        }
        row.className = classes.join(' ')
    }
}
</script>
    <apex:pageBlock >
        <apex:pageBlockTable value="{!rows}" var="aRow" onRowClick="updateRowColor(this)">
            <apex:column value="{!aRow.Name}" headerValue="Name"/>
            <apex:column value="{!aRow.Email}" headerValue="Email"/>
        </apex:pageBlockTable>
    </apex:pageBlock>
</apex:page>

The controller in this case doesn't particularly matter (it's just a wrapper class and a constructor). The magic here is the onRowClick function; here I make it a toggle switch. The function itself receives the TR (HTML table row element) as the single input, which can be directly modified to adjust that row.