I love the entertainment book- I actually only use a few of the coupons but I save much more than the $20 I pay for the book (I prepay/preorder the next yr's book at entertainment.com and usually they will offer a special like you get current year's book free if you preorder next year's).
otherwise, I go to website's like craigslist.org and barter coupons with people- so I can get 5 or so of my favorite place trading with 5 other people who want various places I will likely never go to...