The best team building activities are those that help people bond. Some of the better things that they can do are to have some competitions between various groups with scavenger hunts, board games, or any kind of game. It is also great to give the team the time to relax with one another so that they will choose to get to know each other better during that time. They can get a campfire going and sit around and share stories about their lives, or they can go out for a nice meal together to have the chance to talk then, too.
It is great for team building activities to be all about getting people away from the work environment and doing something that they might enjoy. It can be fun to get everyone painting together, and it will be a great bonding experience when they are all trying to paint the same picture. It can also be fun to take a baking class together, as it will get everyone out of their environment a bit. There are all kinds of activities like these that are good, growing, and learning experiences and they are great for a team to do together.
Everyone trying to find ideas for their team needs to think about the people their team is made up of and what they might like best. If they think that everyone would be interested in getting outdoors, then they can make a weekend of team building activities and go camping together. Or if that is too much, then they can just go hiking together. The more they do anything together outside of work, the better they will get to know one another. The better they know one another, the better they will get along and help each other accomplish great things at work.