“ Societies of beings who in some way reflect the dogmatic, superstitious, religious, idiotic, political, etc. views of large (or small) groups of people in real life.”
“ You come upon a ruined building in the back section of a city park (or other out of the way area of the city). The ruins are fairly overgrown. All that is really standing is a doorway and its frame. If you pass through the opened door, you travel to a different world. If the door closes, there may not be a doorway back to get you back.”
“ Adventurers are to capture an unknown monster for examination (for a sage or wizard) but they are themselves captured by the monsters, and researched.”