Weblogs are comments on things at some given point in time, so it makes a lot of sense navigating a weblog via a calendar view, a prime candidate for AJAXification.
The basic idea is that each page have a default calendar view of the
<div>, and then override that with some DOM scripting, fetching the calendars
from the server so you can scroll back and forth through the months without
that stupid and unnecessary page reload. About the same as the ASP.NET Calendar control if I
recall correctly, but portable. Pretty basic AJAX I guess, and probably
on the 20th to late on the 26th.
Whether the server side month views are preprocessed or generated by server-side code doesn't really matter, but preprocessed and read from disk is always faster.