- Alan Turing and the Unsolvable Problem To Halt or Not to Halt - That is the Question, The first of four lectures on The Turing Legacy held on Thursday, 26th April, 2012 at the University of Auckland.
- Can Randomness Be Certified by Proof?, NKS 2008: What is Computation? How Does Nature Compute?, Bloomington, USA, 2008. Video
- Incompleteness: A Personal Perspective, Google, Mountainview, 2008. Video
- Can Peano Arithmetic Prove Randomness?, TCS: From Foundation to Application, Nis, Serbia, 2009.
- Algorithmic Randomness: A Primer, ENS, Paris, 2009.
- Accelerated Turing Machines: Computational Space and Power, Hypercomputation Workshop, Ponta Delgada, Portugal, 2009.
- Finite-State Randomness, UWO, London, Ontario, Canada, 2010.
- The Complexity of Mathematical Problems, Dynamics of Complex Systems, Valparaiso, Chile, 2011. Video
- Probability, Randomness, Entropy: Convenience or Necessity?, ENS, Paris, 2011.
- How Random is Quantum Randomness?, Asian Logic Conference, Wellington, New Zealand, 2011.
- Alan Turing and the Unsolvable Problem: To Halt or Not to Halt-That Is the Question, University of Auckland, New Zealand, 2012. Video
- The Halting Problem Revisited, The Incomputable, Chicheley Hall, UK, 2012.