I've been using PHP with all of my sites the past 3 years and am about 1/4 of the way through Agile Web Development with Rails. I have a couple of questions and would appreciate it if someone could answer them.

Should I just use RoR on websites that require database connections on just about every page? I'm confused about when to use PHP or RoR or would it be best to just use RoR all the time?

How about in this example? Say I have a site that has 15 pages, only one of which that displays info from a database for a calendar. Would it be better to use PHP or RoR in this situation?

In PHP I use includes a lot for templates for my header, footer, sidebar, etc. Can someone give me an example of how to do this in RoR? Is this what most sites running RoR do or do they just have the header/footer on multiple pages? I like using includes because then I can just update one page when I need to make a global change.

If someone who knows HTML were to ask what RoR is, what would be a good way to explain it in laymans terms (instead of just saying it's a web-based framework that uses the ruby scripting language)?