Dungeon Crawl Stone Soup is a free rogue-like game of exploration and treasure-hunting. Stone Soup is a continuation of Linley's Dungeon Crawl. It is openly developed and invites participation from the Crawl community. See http://crawl.develz.org !
Really fun RL, but SF is not up-to-date, now version stone_soup-0.18.1, moved to a github. (Low rated only because SF is a year out-of-date.)
just try tritank, a tactics strategy shooter coded in c++ and opengl, then u will experience the unexperienced! its yet in development, but try it out and keep updated!