A lecture series by The Teaching Company called "The New Testament" taught by Bart Ehrman is an enjoyable academic introduction to the history of Early Christianity.
I also recommend another lecture series called "From Jesus to Christianity" by The Modern Scholar taught by Thomas F. Madden.
I know it's been a long time, but alongside the horsemen of atheism and reading the actual bible, The Teaching Company is where I got so much of my education.
I also recommend another lecture series called "From Jesus to Christianity" by The Modern Scholar taught by Thomas F. Madden.