In Dungeon Lords, you are an evil dungeon lord who is trying to build the best dungeon out there. You hire monsters, build rooms, buy traps and the other usual stuff.
From the publisher's webpage:
Have you ever ventured with party of heroes to conquer dungeons, gain pride, experiences and of course rich treasure? And has it ever occurred to you how hard it actually is to build and manage such underground complex filled with corridors and creatures? No? Well now you can try. Put yourself in role of the master of underground, summon your servants, dig complex of tunnels and rooms, set traps, hire creatures and try to stop filthy heroes from conquering and plundering your precious creation. We can guarantee you will look on dark corners, lairs and their inhabitant from completely different perspective!