The D. C. S. Oosthuizen Memorial Lecture at Rhodes University, dedicated to the memory of the philosopher D. C. S. Oosthuizen, was founded in 1970 and is held annually.
The lectures are organised by the university's Academic Freedom Committee.
http://dcsoosthuizen.blogspot.co.uk/ (a memorial site to D. C. S. Oosthuizen) has further links to a number of the lectures