I may have mentioned on the site before that I am something of a fan of podcasts. Thats underplaying it a little....my iphone is jam packed with all sorts of podcasts from all sorts of sources. Ideal for taking in quiz information, cementing knowledge and above all else a very enjoyable medium. Most podcasts are free meaning the makers often aren't tied to trying to "appeal" to everyone and work under freedoms they may not have had in TV and Radio.
History According to Bob is one such podcast. Bob is a passionate history professor and over the years has covered a range of subjects on a variety of podcasts. Everything is explained well with plenty of facts and its ideal fro a quick brush up on key events in history and an ideal launch pad for further reading.
I have spent many hours listening to these shows and enjoyed them considerably. Try for yourself by typing it into the Apple Store or they can be downloaded as MP3's HERE. All free of course.