Ever since Meno I've been taking point form summaries of the Great Books I've been reading and I've found it very beneficial. Writing ideas down helps me to comprehend them and it's handy to have the main ideas from these books easily available (rather than re-reading the entire thing).
The reading of Aristotle's Ethics consisted of Book 2 in its entirety, chapters 5-12 of Book 3, and chapters 8-13 of Book 6. I greatly enjoyed Book 2 and the selected chapters from Book 3 complimented it. However, the selected chapters from Book 6 came across as a little random to me and I didn't comprehend it as much as I did the other chapters.
In Book 2, Aristotle defines a virtue as the mean (i.e. the correct amount) of a quality between excess and defect. For example courage is the mean between cowardice and rashness and temperance is the mean between self-deprivation and over-indulgence. Aristotle also said that virtue is acquired through practice, and that a virtuous disposition cannot simply be willed to happen, it must be put into action. At first you might not like doing virtuous acts; do them anyway and what you imitate will become reality. Eventually, a truly virtuous person will take delight in doing virtuous acts. Ultimately, Aristotle says that a virtuous man "must have knowledge of virtue, must chose to do the acts for their own sake, and the action most proceed from a firm and unchangeable character."
In the selections from Books 3 and 6 Aristotle delves deeper into the virtues of courage and temperance and then talks about intellectual virtue (as opposed to moral virtue), but it was Book 2 that really struck me.
I found this book very practical and good for self-improvement (I'll take Aristotle over a modern self-help book any day!). I've recently been re-reading Mere Christianity and, this time around, I really notice the Aristotelian influence on it. This might seem silly, but one of the initial reasons I wanted to read the Great Books was to gain a better understanding of Lewis's writings. So far it's worked.
Ethics is probably my favourite book on the second list so far, over-taking Herodotus' Histories. I think I still like Herodotus' writing better, but I love Aristotle's ideas.