A number of different companies will offer you a huge variety of different 'team building' activities. This, however, isn't strictly true. Briefly, a clear differentiation must be made between 'team bonding' and 'team building' activities.
Team bonding encapsultes a number of activities, from a group visit to the pub to treasure hunts and paintballing (and a number of things in between)! Essentially, it is an organised gathering where the main aim is for people to have fun and to help break down some barriers. There are no real goals or expectations and the gains are usually quite short term.
Team building has a different emphasis in that it should have clearly stated objectives and the session should be developed with these objectives firmly in mind. This can, of course, take many forms and can be wholly plenary, or wholly experiential. The important thing is for the clearly stated goals to be achieved and achieved effectively so that the team becomes more enlightened as to its function, and therefore becomes more effective.
So, if you are thinking about booking a 'team building' session, bear these differences in mind. Both have their place in organisations, but forgetting the difference may leave you dissappointed with the longer term outcomes from the session!
Andy O'Callaghan