I've been plowing through Brett Terpstra's OS X Shell Tricks over at Mijingo and they are great. Now I find out they are on sale for 50% off and the sale ends today (Sunday, November 30th)
In fact, everything is on sale over there. I'm going to be picking up the PIP and virtualenv video course for sure.
The Command Line Bundle is pretty nice for $20 and includes the Brett's video course.
Here's a nice streaming (and free) example of the video courses: Budgets with Soulver
I like the Mijingo stuff because I can download and save my purchase offline. There's no way I'm going to remember everything in a course, so having instant and easy access to the material from any platform (that supports .mov) is pretty nice. It can also be streamed if that's more your thing.