When organizing a team building activities or exercises within your office, you need to initially group the different employees into different teams. It is always good to group the employees into different team in such a manner that each of the teams is balanced with respect to skill or potential. It is always good start with the light or warm up activities, you could consider progressing afterwards with challenging tasks. You can always include some team building games in each session regarding the activities. For learning about some of interesting games or activities that you can include in such sessions, you can consider resorting to the sources like internet or magazines. Always see that you choose activities that will help to improve the skills and thinking capacity of the employees.