Nice bulbs,  i like how your camcorder makes the bulb go all colourful in time.

Several of the "slow" instant start electronic CFLs (Includes the recent Philips Genie CFLs) behaves like these powergrooves during ignition despite their ballasts is significantly different and also their ignition mothed (Powergrooves uses rapidstart magnetic ballasts).
Rapidstart magnetic ballasts and all electronic ballats for argon buffer based fluorescents that emulate the rapid starting of these magnetic ballasts warms the electrodes while applying to the tube its operating current without any high voltage (One of the reason why Krypton can't be used with these ballasts). After a few seconds, when the electrodes heated enough, the lamp stabilizes itself. In instant start CFLs on the other hand, the ballast send to the lamp a high voltage and a lower current to operate it in cold cathode mode and then transfers the operation to hot cathode modes. Despite this, several instant start CFLs, like the recent Philips Genie lamps, lits exactly like these powergrooves in this video which uses magnetic rapidstart ballast. Why?

Is that a lead-lag ballast? I'm just wondering why the lamps seem to be "firing" at different times.

Nice light!

I don't recall the info on the ballast, I know it is an Advance rapid start VHO.
In person, the bulbs don't blink or flash. I guess they are really doing that but with out the camera...you just can't see it.

What you are seeing is frequency switching, since US power runs on 60 HZ, the camera can see it, and it makes the lamps appear to flash, but you can't see it with your own eye!

That is indeed the lead-lag effect, or "stroboscopic correction". Most magnetic ballasts, including the popular Tulamp preheat ballast use that configuration.