A long time ago I first learned about Jack Vance's Dying Earth stories in Appendix N of the AD&D Dungeon Master's Guide. The D&D magic system, where magic users could memorize only a specific number of spells, was taken directly from this series, as were many of the spell names (prismatic spray, anyone?). I've read all four novels several times, and thoroughly enjoyed Vance's strange, richly detailed world and the very fallible people living in it. All four novels are now available in a single volume, Tales of the Dying Earth, and if you haven't had a chance to read these, please do so.
Vance, a prolific writer in several genres, hasn't written any new Dying Earth stories in a long time. Lucky for us, other writers have stepped into Vance's world of powerful sorcerers, odd creatures, demons, and antiheros living through Earth's last days before the red sun finally goes out. Their stories are collected in Songs of the Dying Earth, and what a rich collection it is! Filled with 22 short stories by such great writers as George R.R. Martin, Robert Silverberg, Kage Baker, Neil Gaiman, Tanith Lee, Glen Cook, and Mike Resnick, and also including the novella, "The Guiding Nose of Ulfant Banderoz," by Dan Simmons, this collection will satisfy even the biggest Vance fan. I've read through about half of the stories so far, and haven't found a bad one yet, which is a tribute not only to the writers and editors, but to Vance's world, which seems to bring out the best in fantasy writers. I highly recommend both Vance's work and this collection to any fantasy reader, but especially to RPGers and game masters, as there are some fantastic ideas and constructs within these pages that can be added to your game.