1. A method for threshold activation of an audio teleconference, the method comprising: reserving an audio conference for a specified set of callers; setting a pre-determined threshold number of calls for activating the audio conference; receiving calls into a conference bridge for the reserved audio conference; adjusting the pre-determined threshold number of calls responsive to receipt of a pre-specified event other than a number of calls received; determining whether or not the adjusted pre-determined threshold number of calls have been received into the conference bridge; and, initiating the audio conference responsive to the adjusted pre-determined threshold number of calls that have been received into the conference bridge, but prohibiting initiation of the audio conference until the adjusted pre-determined threshold number of calls have been received into the conference bridge.