Administered by the Hochschule Augsburg, this online library contains e-texts in multiple languages, with an entirely Latin interface (caveat lector!).  There are numerous writings in both the Bibliotheca Latina and the Bibliotheca Graeca, including from Late Antiquity, where both Christian and non-Christian authors are well represented.  Most patristic texts are reproduced from critical editions subsequent to Migne (apparatus not included, of course); images of authors are sometimes included, as well as basic introductions (again, in Latin!).  While of necessity this site contains only a selection of Late-Antique religious texts, it is a generous one, especially given the minimal coverage this period receives from the Perseus Digital Library.  Highly recommended!

http://www.hs-augsburg.de/~harsch/augustana.html