Since 2002 Perimeter Institute has been recording seminars, conference talks, and public outreach events using video cameras installed in our lecture theatres. Perimeter now has 7 formal presentation spaces for its many scientific conferences, seminars, workshops and educational outreach activities, all with advanced audio-visual technical capabilities. Recordings of events in these areas are all available On-Demand from this Video Library and on Perimeter Institute Recorded Seminar Archive (PIRSA). PIRSA is a permanent, free, searchable, and citable archive of recorded seminars from relevant bodies in physics. This resource has been partially modelled after Cornell University's arXiv.org.
After reviewing the cosmological constant/dark energy problem(s), I will present a dynamical mechanism wheiren a gap forms turning the unstable perturbative gravitational vacuum into a non-perturbative vacuum. Similar to the BCS theory this mechanism reflects the formation of Cooper-pairs which can cancel the would be large cosmological constant. Furthermore, when this mechanism is forumlated in the Ashtekar-Sen variables the cosmological constant problem bears close semblance to the strong CP problem in QCD. Open issues with this approach will also be addresssed.