Being Scholarly about Teaching (this is a long annotated list of scholarship of teaching and learning/teaching pedagogy papers assembled by Brian P Katz)
One page introduction to Standards-Based Grading, Specifications-Grading, and Ungrading by Drew Lewis
Andrew Cooper's real analysis blogging assignment and their blog.
Evelyn Lamb's blog post on Blogging in Math (History) Class, and 3010tangents.
Teaching with Blogging by Vanderbilt University's Center for Teaching
Sample writing assignments: Single-variable derivatives, Partial fraction decomposition