Tokyo Coupons is a new concept in Tokyo. This book gives you 50% discount off food at a wide range of restaurants in Tokyo. The book costs 3000 Yen and is available from http://www.tokyocoupons.com. Depending on how much you order you can make the initial 3000 Yen back in one meal. The book acts as a "gourmet guide", introducing a number of fine restaurants and bars. There are over 80 restaurants from 35 different countries. I cannot recommend this book enough. Hurry, the coupons are valid till October 2005.
Quite a few FG hang-outs are listed on the website. The gurunavi site also offers coupons for selected restaurants. There are usually even more on their Japanese page.