I had a nice commute today. On the way in I had a recurrence of the flat that had me phoning for the Support Vehicle yesterday afternoon. But unlike yesterday, it wasn't really a bad blowout, and after the fiasco yesterday I had converted my frame pump to inflate Presta, so I was just able to pull over at a bus stop and re-inflate for the last two miles.
Patched up at work and actually FOUND the metal splinter root cause -- it had punched right through last nights patch! Stopped at LBS on the way home and bought a couple of replacement tubes. Had a nice snappy, fully inflated ride home.