Hey there it sounds like it will be a blast because you know retreats always are ecspecially away from home. Anyways this little game that me and my sisters do sometimes and we do this at church retreats as well is take some rolls of toilet paper with you. Encourage people to tear off enough of the roll because they don't know what they will need it for. Then when everyone gets how much they want then start the circle off and for every sheet you have thats one thing that you have to say about yourself, or someone around you, or maybe something that you like to do, or what you expect to get out of the trip. It seems like a small game and maybe a little childish but it is one way for everyone to talk and be open and for everyone to learn a little about each other.
One other thing that we always do on bid night and this is when we buy a hotel suite and pile 15 girls in and when we pick everyone up we make sure and tell them to bring one thing that is more important to them than a lot of other things rather it be a picture, blanket, a memorble keepsake, or anything that has importance. Then in the same way as above go around in a circle and let everyone tell why its important and sometimes tears are shed and laughter is out of control and it only brings ever one closer.
Good Luck
New Mexico State Aggie