We use a sign in sheet every meeting and when they do extra hours students are supposed to sign in when they begin their extra hours and sign out when they leave and have a mentor sign off on those hours.
We use a star chart to keep track of student achievements during the season to determine if students deserve to travel with the team or not. The Star chart measures attendance. community service, oral presentation, fund raising, academic performance during the build season and extra credit (I'm probably missing something).
This is a picture of the star chart in 2010 in the middle of updating by our lead teacher.