Ranking Tasks - a collection of a ranking tasks for students of all levels of physics
E&M TIPERs - Tasks Inspired by Physics Education Research; a collection of ranking tasks, working backwards tasks, qualitative reasoning tasks, etc. all related to electricity and magnetism
Newtonian TIPERs - more tasks, this time related to mechanics
Sensemaking TIPERS for Introductory Physics - more tasks, originally geared towards the high school population, but also for the college introductory course.
Peer Instruction - Eric Mazur: a method for interactive engagement and student discussion.
Five Easy Lessons - Randall Knight - strategies for effective instruction
Teaching Introductory Physics - Arnold Arons - a classic with a good discussion of misconceptions and some good conceptual homework problems.
Physics By Inquiry - U Washington PER Group - A series of modules designed to help students learn by doing.
Tutorials In Introductory Physics - U Washington PER Group - Designed to supplement the lectures and labs in an introductory physics course at the college level
Fletcher Conceptual Manual - A source of conceptual questions for many topics of physics