Call center agent training is provided on a non-scheduled basis and is characterized as having a duration that is less than a scheduling interval used to schedule the agent for their work shift, as well as schedule other activities in the work shift. The delivery of snippet training content may be triggered by various conditions, including in response to: a request for training originating from the agent, a period of continuous call processing activity of the agent, various agent performance metrics, or probabilistically assigned to an agent in a group. Various parameters may selectively limit provision of a snippet training session. The agents provided with training are placed in an unavailable state prior to the snippet training session, and placed back into an available state afterwards. The snippet training content may be variously structured and can be grouped together to form an e-learning course delivered to the agent.