'Attract-o-Meter 3000' was created alongside other campaign elements, which included paid-for banner ads on other sites, media partnerships with companies and radio interviews.
It asks tongue-in-cheek questions so visitors to www.attract-o-meter.com can measure their attractiveness, and ends by proposing that they click through to www.do-it.org.uk to appear more loveable.
The game led more than 168,000 unique users to the volunteer site in May, representing an almost ten-fold improvement on previous monthly figures of 17,000.
The campaign also prompted 44 per cent of the people who clicked through to register for a volunteer opportunity. This figure equates to 13,000 and goes some way to reaching year-end registration targets of 33,000 set by the Active Communities Unit, which funded the campaign with £270,000.
"This campaign has been great news," said Maddy Heil, the charity's communications manager. "We have been able to build up a database of why people volunteer so as to inform future campaigns, and it gives us hard figures to attract future corporate and government funding."