Although I don't talk about it nearly as much (other than popping up on occasion in my reviews of fiction I've read) another mode of fiction that I really enjoy nearly as much as fantasy is old-fashioned space adventure stories of the kind that was popular in pulp fiction of the first half of this century, and subsequent cheap, mass market paperbacks. This mostly comes in two very similar forms, the Planetary Romance (and the Sword & Planet which was essentially the same thing revitalized and copied several decades later) and the Space Opera.
Space opera in particular saw a resurgence of popularity when George Lucas adopted it as the genre for his movie epic Star Wars, and several similar movies and TV shows were quickly made, and continue to be made. But as much as I like the original Star Wars movies, and the whole genre in which they operate (and I do, quite a bit) there's something about the older stories that calls to me more. While most of them (like everything else published in the pulps) was gratuitous in its presentation of adventure, danger, exotica and lurid erotica (sometimes) there's also some great stories here that feature astonishingly well-crafted stories. Authors like Edmond Hamilton, Ray Bradbury, Leigh Brackett, C. L. Moore and others follow in the later Space Opera tradition, while Edgar Rice Burroughs and his imitators (including Otis Adelbert Kline, Ralph Milne Farley, Alex Raymond and even Robert E. Howard) pioneered the genre with the even less scientifically rigorous swashbuckling planetary romances. In the 1960s, Don Wollheim (and others) popularized a revival of planetary romance, redubbing the revived retro-genre as Sword & planet, and putting out copy-cat works by the likes of Alan Burt Akers, Michael Moorcock (writing under a pseudonym), Mike Resnick, Gardner Fox and others. And, as usual, Lin Carter and L. Sprague de Camp imitated both in their own works too.
Frankly, I think its this same cheap, almost exhibitionist (and certainly gratuitous) use of things that a young boy would find "cool" (maybe "swell" would be a better adjective given the timing of publication of a lot of this) which was often present in sword & sorcery, as well as pulp "mainstream" adventure and mystery stories that makes it fun. Granted, if that's all it's got, the work isn't going to be very good, and a number of my past reviews certainly highlight that flaw in a number of works. But a well-written book that also has that kind of "gee whiz!" fantasy or science fiction pulp influence can be tons of fun, and I've often adopted that kind of flair for most of the RPG campaigns that I've run.
I haven't done much specifically with this genre in my roleplaying, but I think that's been a sad mistake that should be somehow remedied.