After seeing the [My First Character] thread a while ago and it newly popping up in my inbox for some reason, I thought I'd add a scroll where players could share their introduction to roleplaying.
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.