Music
He spent five years learning to play west-African percussion (Djembe, doun-doun), studying with Mamady Keita and others in Brussels, and playing regularly for Senegalese and Guinean dance teachers in Antwerp and Brussels. He is currently teaching himself to play guitar.
Writing
His unpublished writings focus on evolutionary sociology, the science of understanding how our societies work by looking at our past. He has developed and refined theories of behaviour that he applies in his work (for example, that product design, including user interfaces for software, is a gender-sensitive issue, or that male and female networks work differently, so need different kinds of software support).
He has developed a theory of burnout that he uses in his work with volunteer groups, including the free and open software projects he works on, and the FFII.
Travel
He has travelled extensively, professionally and privately, having spent time in Congo, Kenya, Tanzania, Rwanda, Angola, Burkina Faso, Nigeria, Togo, Sri Lanka, Belgium, Canada, Scotland, England, Portugal, France, and the United States.
Associations and Clubs
He is a member of Rotary International, Mensa, and the FFII.