Developing cohesive Project Teams when the team members keep changing

We all know how critical developing a cohesive, high energy project team environment can be to the success of a project. Technques for team bonding include off-sites, dinners, joint outings, sports activities, social activities, cultural activities, etc. However, with many teams working 10 hour days, time for social activities is limited. Developing a cohesive team is made even more difficult when the team members leave and join the team.

Please share techniques that you have used to increase team cohesiveness.

One of my favorites, particularly with multi-cultural teams, is to do something with traditional foods of the different cultures represented on the teams. In the past, we have done apartment cooked meals hosted by team members and take-out where more practical. Team members talk about the various foods that we are eating and give some background on the ingredients used. A good time is generally had by all.