Diana Larsen has commented about the building blocks she thinks are fundamental to Agile. I have held a theory for a while now that iterations and retrospectives are all that is required for an agile process to evolve. I can imagine that first retrospective discussing items like "Hey - our communication isn't so good. Lets try having stand-ups next iteration." Similar conversations could occur for any practice discussed by the agile community. Bootstrapping practices in a team can accelerate the evolution of the process, but it also means imposing more decisions on the team rather than having them manage themselves. Mileage will vary widely depending on your people.