Tales of Middle Earth
Tales of Middle Earth (ToME) is a fantasy adventure game, based on the works of J.R.R. Tolkien. It is a game that emphasizes intricate, challenging, and varied gameplay over graphics. Hundreds of different monsters in randomly-generated, unpredictable dungeons will strive to slay you by various means, and you counter - if you survive - by developing the skills of your choice and wielding mighty artifacts. ToME's races from Hobbit to Troll and classes from Swordmaster to Summoner allow for many different playing styles and a replay value that extends through years.
The only game so realistic that your scrolls and spell books will burn if you trudge in lava (unless you have gained immunity from some armour), you will dry up rivers to cast mighty spells, strike at orcs with blades attuned to slay them specifically, summon armies from a simple totem, and even forge your own artifacts. There is an entire community to help you with the game, and it is far from static - ToME is a developing game, always improving. And best of all, it's free.