While I love using PowerPoint slides as much as the next person, sometimes I find that unrolling a printed diagram and placing it on the table and getting everyone to review a sample SharePoint Logical Architecture Model is a wonderful way to introduce SharePoint concepts that are hard to grasp in other ways.
There is a white paper that describes this architecture model on TechNet, titled Logical Architecture Model: Corporate Deployment. This architecture description includes a link to a visio model, Design Sample: Corporate Deployment Logical Architecture. I took this file and had FedEx*Kinko's print me up a couple of dozen of this printouts, and when appropriate, I hand them to SharePoint administrators when I have this discussion with them.
The basic idea is that a SharePoint Farm for the Fabrikam company is described within this model. There are two SharePoint farms, one that includes the Intranet and the Partner-facing Extranet application, and one farm for the Public Internet site. Within this model, the following SharePoint concepts are illustrated:
It's all good stuff. This is a model that keeps on giving back insights into SharePoint architecture beyond the first review. Post it somewhere on your cube wall and when the day gets to tough, take a few minutes to gaze upon this model and simply allow the SharePoint sweetness to soak in.