The first incident was the assault on the Red Mosque in Islamabad (which militants claim took the lives of 1,500 people, mostly students). This incident fixed the target of the insurgency (the Pakistani military and not NATO next door in Afghanistan). It also generated sufficient motivation for violence. The second has been a series of examples of successful attacks against the Pakistani military. Specifically, suicide-bomb attacks against military targets (at a recruitment center, a convoy, a patrol, and several checkpoints -- with over 100 killed).
With a plausible promise in place, all that is needed is a pool of new groups to participate. That may already be present. The intrepid Syed Shahzad, of the Asia Times, reports that there is a host of rapidly growing networks of insurgents outside of the control of traditional groups (which makes them relatively immune to government coercion/negotiation):...the present breed of jihadis rapidly emerging in the Swat Valley, Bajaur, North Waziristan and South Waziristan is different.If true, Pakistan may devolve much faster than anticipated. Will we see it hollow out?The militants this correspondent encountered could hardly be called "revolutionary" [in the sense they don't have a plan for Islamic governance], and they were not fully trained combatants. At best they could be described as disgruntled youths who have been manipulated by clerics, or simply fired up by incidents such as Lal Masjid.
They are up in arms and want to take on the government. They say they want to kill Musharraf, but they don't know how, or what they would do next. This scenario promises to generate serious violence, but not revolution. The militants are divided into small groups, united only in a desire to fight their common enemy, the Pakistani military establishment.