Great Way To Study/Expand Vocabulary While Having Fun

I know this isn't as intensive as on the GRE but I have just started studying for the GMAT and, outside of the normal studying procedures, I also resolved to start reading a lot more. I used to read a lot but since high school haven't read much in terms of fiction, and this presented me with a great opportunity to do so. I've picked up a bunch of the classics, some of which are on the GMAT book list thread here, as well as Foucault's Pendulum by Umberto Eco. I've also picked up a small Moleskine notebook. As I read through a book I'm underlining words that I don't completely understand. In the notebook I'm writing down the page number on which they occur, their definition, the definitions and sources of their roots (usually Greek or Latin), as well as some synonyms. I'm then going back over the section I read and reading it over again, referencing any underlined words in my notebook if I don't completely remember it.

Usually I can get a rough understanding of words' meanings based on their context and roots, but that doesn't stick with me enough to actually understand the word, so this process is really helping me. It's exhausting when going through an Eco novel for sure, but it's really satisfying. I'm not sure where I'm going to go with this but I think once I get through a book I'm going to work up some flash cards or something from the words I wrote down, as well as their roots.

I'm hoping this will drastically improve both my vocabulary, understanding of roots, and reading comprehension. Having an engineering background, I'm assuming quant will be my best section by far, so I'm really hoping this will bring up my verbal scores drastically.

This is also a really fun way to expand one's vocabulary, and has really helped me sit down and absorb a book in a more complete way than just skimming over words and getting a vague understanding based on their context. I'm finding I get a lot more out of reading when I do this.