I enjoy watching about anything on animal planet, syfy or the discovery channel, but for series type shows that run in the summer I really like the TNT lineup: Leverage, Memphis Beat, HawthoRNe, Men of a Certain Age, Rizzoli and Isles, and The Closer. A new sci-fi series on TNT called Falling Skies is looking good, it premiered on the 19th and will be on Sundays. It's basically a War of the Worlds type show starring Noah Wyle who you probably know from ER and The Librarian.

Or use this link to watch full episodes online.