I use NLSY with my Methods II class. They choose the variables themselves, download the data from the website, and clean it (nothing major). It's a rich source of data with many many variables, so it suits many interests. I used to offer also Add health public use data, but NLSY was really enough. Occasional students have chosen to use datasets from the Department of Education, such as ECLS.
I use YRBS, which is cross-sectional, for the Methods I (first semester) class projects. Occasional students have chosen to use the National Survey of American Life, rich cross-sectional data about African-American and Afro-Caribbean populations, and the General Social Survey.
Alternatively, there are sources of data in R libraries, such as the Mosaic library in R has the HELP trial, which is pretty interesting and rich enough for a project.
Janet
Janet Rosenbaum, Ph.D.
Assistant Professor of Epidemiology
School of Public Health, SUNY Downstate Medical Center, Brooklyn, NY