If you fancy ASCII graphics, Dwarf Fortress has amazing gameplay. If you don't, you can install fan-made tiles to make the graphics more recognizable.
Basically in that game, you build a fortress for dwarves inside a mountain (or on it, up to you). In the fortress, you can build many rooms, such as farms, workshops, barracks, blacksmiths, and also.... traps. You dwarves have at least 30 professions to chose for and each of them has his/her own unique personality.