eve online
A science-fiction MMORPG developed by Icelandic company CCP Games. It is currently the only single-shard MMORPG in existence, meaning all players share a single world (called New Eden) of over 14,000 star systems, running on the gaming industry's most powerful server.
Players take control of a 'capsuleer', an augmented human (there are no alien species in the universe, with the possible exception of the reclusive Jove, who were originally humans as well, but have undergone extensive genetic modification, resulting in what is practically a new species) whose consciousness is transferred to a clone in the event of death, making the capsuleer immortal. Capsuleers travel in small capsules (hence the name) that protect them from various dangers in space, and which, in turn, are docked into larger ships, creating a conduit between the capsuleer brain and the ship systems in order to pilot the ship.
Expansions used to be issued twice a year, but towards the end of 2014, CCP Games switched to a release cycle of 4-6 weeks between expansions.
The game is (in)famous for its steep learning curve, stemming from the many opportunities and possibilities players are faced with, all of which are available from day one.