A major criticism of the American Time Use Survey (ATUS) is that, with the exception of childcare, the survey does not systematically collect information about activities respondents did while they were doing something else. The ATUS focuses on collecting information about respondents' main (or primary) activities; when respondents volunteer that they were doing secondary activities, this information is recorded by the interviewers, but it is not coded and does not appear in the final data. This study is an analysis of these additional secondary activity data from 2006. The study provides descriptive information about who reported secondary activities and the activities they reported. It also quantifies the secondary activity time that was spent in nonmarket work and examines whether the omission of these data impacts valuations of nonmarket work. Finally, it evaluates the quality of the voluntarily-reported secondary activity data.