Likely Healthy

Nutrition for Health Promotion and Disease Prevention - UCSF -  Katie Clark

Contraception: Choices, Culture, and Consequences - UCSF - Jerusalem Makonnen

Principles of Obesity Economics - Johns Hopkins University - Kevin Frick

An Introduction to the U.S. Food System: Perspectives from Public Health - Johns Hopkins University - Robert S. Lawrence, Keeve Nachman

The Social Context of Mental Health and Illness - University of Toronto - Charmaine Williams

Community Change in Public Health - Johns Hopkins University - William Brieger

Vaccines - University of Pennsylvania - Paul Offit

Gamification - University of Pennsylvania - Kevin Werbach 

Seriously, check out Coursera.