At our date parties, each sister would invite one man. The men would be told about the event, but not who specifically had invited them. If a particular man was unavailable that night, the sister who'd invited him would provide a second choice.
At the event, it would be revealed who invited whom. One year, everyone got keychains, and the men had to find whoever had the matching keychain - the keychains then became the favors. Another year, the men were asked to wear ties, and as they arrived, they handed their tie to the social chair and went into one room... we were in another room, and the tie was given to the sister who'd invited him... and when everyone had arrived, the men were brought in and had to find their ties (and hence their dates).
We'd hang out for a while, have some non-alcoholic drinks, then go out to dinner at a restaurant.
The arrangement worked very well, because sisters who had boyfriends or fiances simply invited their SO's. Obviously, those guys would know in advance who'd invited them...
