The goal of the PADS project, which started in 2001, is to make it easier for data analysts to extract useful information from ad hoc data files. This paper does not report new results, but rather gives an overview of the project and how it helps bridge the gap between the unmanaged world of ad hoc data and the managed world of typed programming languages and databases. In particular, the paper reviews the design of PADS data description languages, describes the generated parsing tools and discusses the importance of meta-data. It also sketches the formal semantics, discusses useful tools and how can they can be generated automatically from PADS descriptions, and describes an inferencing system that can learn useful PADS descriptions from positive examples of the data format. Categories and Subject Descriptors D.3.m [Programming languages]: Miscellaneous General Terms Languages, Algorithms Keywords Data description languages, ad hoc data, domain-specific languages