I have seen a number of these sprouting up and many dedicated to the "Golden Age 1980's" RPGS, but also some of the more recent but less known PNP RPGS as well.
There is a resurgence of interest in:
Star Frontiers
Twilight 2000
Conan RPG (TSR)
Top Secret
Also some not so old:
White Box
Myfarog
And finally some soon to be released:
REH's Conan RPG
John Carter RPG
I'm curious what others here are playing, looking to play or might be interested in playing.