I recently published "The Art Teacher's Substitute Notebook: K-2 Lessons." It is a compilation of 12 complete lessons for the art teacher to leave on her desk in case a sub is necessary. Maybe you aren't interested in 12 complete lessons right now... don't worry, you can pick and choose one at a time! Click the links to learn more about each lesson.
Now available, It's a Zoo! This lesson concentrates on basic shape drawing and composition skills. Comes with an easy "how to draw" page and very detailed directions.
Also available, Big Butterflies. This lessons concentrates on balance and pattern.
Available for free is Candy House. This lesson combines fairy tales and architecture and has great illustrations and a brainstorming page.