Hi, this is my first post, I happened to be playing unNethack before going to sleep on December 1st.
Somehow I managed to stumble into a magic portal from level 2 to a level filled with gems and small rooms numbered 1 to 24. Only the first room was unlocked and the other doors couldn't be opened with a key, Also, kicking and using force bolt didn't help. I dont know the teleport spell yet, but I'm betting it wouldn't work on this level.
It wasn't until I tried to look it up on your wiki that I realised the level was called Advent Callendar