Run only a single test case within your testing file

ruby my_testing_file.rb --name test_casename

This isn't a benchmark, but it's a great way to send a lot of requests to your box and check if there's anything wrong with your FastCGI setup:

for url in `cat urlslist.txt`;
do
    COUNTER=0
    while [  $COUNTER -lt 2 ]; do
        echo -n ${COUNTER}-
        curl --silent --user yourUSER:yourPASS $url | grep "Internal"
        let COUNTER=COUNTER+1 
    done
done