They have a lot of back issues, but it's especially timely now that Wizards of the Coast have started offering up older editions of D&D to download. There's so much inspiration between these pages that you could spend days just reading them.
[edit: as you may/or may not have noticed The Dragon and Polyhedron links no longer work]
And the good news continues because they also have available;
- Ares Magazine
Ares was a science fiction wargame magazine published by Simulations Publications, Inc. (SPI), and then TSR, Inc., between 1980 and 1984.
- Polyhedron Newszine
Polyhedron was a magazine targeting consumers of role-playing games, and originally the official publication of the RPGA (Role Playing Gamers Association).
- The General Magazine
The General (1964–1998) was a bi-monthly periodical devoted to supporting Avalon Hill's line of wargames, with articles on game tactics, history, and industry news.
- The Space Gamer Magazine (Wargames)
The Space Gamer (TSG) started out as a digest quarterly publication of the brand new Metagaming Concepts company in 1975.
And just for fun there's;
- OMNI Magazine Collection
OMNI was a a science and science fiction magazine published in the US and the UK. It contained articles on science fact and short works of science fiction.
- Starlog Magazine
Starlog was a monthly science-fiction film magazine published by Starlog Group Inc. The magazine was created by publishers Kerry O'Quinn and Norman Jacobs.
- Galaxy Magazine
Galaxy Science Fiction was an American digest-size science fiction magazine, published from 1950 to 1980.