Between Oxford University, the museums, and an assortment of other research institutions, there's an excellent range of talks, lectures and seminars on in Oxford.
There is a fantastic Oxford Talks site run by Linacre, which aggregates allmost of the different seminar pages and provides services such as email alerts! (Though I think it only covers Oxford University).
Oxford Uni also has a a general what's on list and listings in the gazette (which sometimes have events that don't make it into Talks), while the Daily Info has a Lectures, Seminars and Conferences listing.
Suggestions and additions from me? Not bloody likely. But Oxford certainly lived up to its reputation at the forefront of human knowledge judging by the number of seminars and workshops. Its right up your alley as you have an insatiable inquisitive mind. Make the most of your sojourn in Oxford.