The Faculty of Law have hosted some interesting visitors over recent years, and now you can listen to or watch them in the comfort of your own flat / chair in the library / playing field / bus - you name it. Many of the seminars are recorded in video and/or audio, and include F.W. Guest Memorial Lectures, Inaugural Professorial Lectures, and Symposia. A recent visitor was Lord Phillips of Worth Matravers, speaking on "The Impact of Human Rights on Domestic Courts".
For other great lectures, head to the Faculty of Law Podcasts.