I believe this forum is for the workshop being offered at NIH in the near future. (And I can highly recommend it having attended a session many, many years ago.)
Periodically, Accelrys offers a CHARMm Workshop for new and inexperienced users. There are also occasional sessions on more advanced topics. Please see the Meetings and Events forum for dates and locations.
I am not aware of other CHARMM/CHARMm workshops being offered in Europe.