I understand Rashid's point about the service projects being a benefit of membership but in the interest of attracting service minded members I would encourage members to bring 1 or 2 friends to each service event for the semester. It'll give prospective members a chance to see how you operate and if it's something they'd be into. Honestly for a service centered group I would have more than half of your rush week activities be service oriented. Bowling, batting cages, mini golf, etc are good activities to get to know people but they are not a realistic snapshot of the day to day activities.
eta: Update the chapter website.
