In case you missed the DTrace demo during the JavaOne keynote, you can view it in RealPlayer format here. To skip to the DTrace stuff, jump 1:12:30 in. I haven't actually been able to bring myself to watch it -- I'm too self-conscious -- so feel free to comment on it. Things to keep in mind when watching: I can type better when I'm not in front of 7,000 people and I'm well aware that I need a hair cut.
That guy next to me is John Loiacono (not to be confused with Laocoon, the tragic figure of Roman epic).