I started this earlier today, trying to make a <1/2KBRL. I didn't succeed. By the time I was done, I had a roguelike which took 7 and a half hours, and was 4.4KB in source code size. So it's a <5KBRL which is just as fine with me. Since it was done in 7 and a half hours, it's also an 8HRL I suppose.
It's pretty simple, you are Beowulf, diving through Grendel's lake to kill Grendel's mother at the bottom. You have a limited amount of health, and there is no leveling. The goal is to reach the bottom of the lake (Level 8 ) and kill Grendel's mother. Pretty simple, but it has a nice dungeon generator. I'm happy with it!
It's only story is various text quoted from Beowulf.
You can download it here:
http://code.google.com/p/dreamhack/downloads/list