Back in 2005 I had given a couple of talks at the Dublin ICT Expo – one on Asterisk, and one on Xen. Two of my favourite technologies at the time (and still are!)
For posterity (and because I have not put anything else into my Asterisk section), here is the Asterisk one. The Xen presentation is here
ICTExpo_2005-Asterisk-Barry_Flanagan