More extensive projects
Singing (together) offers more possibilities. The teamspirit can really be stimulated by transforming management or all personnel into a real choir and rehearsing with them as a preparation for a party act or an inauguration performance. Any group large enough can sing in a two- or three-part-harmony, and this has an incredible effect, both on the group itself as on the public.
Randstad Holding
For the goodbye-party of Randstad's CEO the whole staff of Randstad Holding formed a choir and rehearsed during two lunch-breaks. They performed a ten minute medley as if they had been studying for many weeks.   

ZinThesis (a company of interimmanagers and consultants in IT) invited sixty of its best clients for a yearly customer event. They were welcomed in an old castle for a keynote speech by Jan Kortie about inspiration. After some singing the participants had a choice of four two-hour (musical and other creative) workshops. Then there was dinner and after that there was another hour of community singing, this time with a well known singer as guest-soloist.

Smaller groups 
In smaller groups, singing can help participants to develop their creativity, intuition, leadership, cooperation, presentation and communication skills. Singing is the most direct way of expression, it doesn't require specific knowledge or talent from the participants to be quite effecive as training. At the same time these courses create a clear teambuilding effect: while singing, people show themselves to others in a way that says more than a lot of beautiful words.   
An international Unilever Board held a series of three day meetings to enhance an integration proces after a merger. Apart from dealing with some business issues these meetings were meant to improve the cooperation and to develop the leadershipskills of the participants. During this proces Jan Kortie gave them a couple of three hour workshops in which they improvised solos and duets. Also they acted as choir-masters, to get some more insight and practice in the kind of authority that people experience as inviting.

For more than fifty (almost only male) managers a two day seminar about quality improvement was organised. The program of the evening was a performance by a famous Dutch singer  built on the theme of the meeting, combined with a singing workshop directed by Jan Kortie. At the end of the evening the managers were singing as a real choir, with a professional soloist, and they still regret that it is not recorded on a CD.