Khara Khang's Random Rainbow Maze by Ken St.Andre
This is a really nice little adventure from the Troll Lord himself.
It's difficult to write a full review without cheating and reading sections I haven't reached yet. I've been killed a couple of times so far, so I recommend taking in a delver with a pretty hefty weapon.
It appears adaptable to most of the T&T rules editions (I'm 5th edition fan currently playing 7.5)
Ken St. Andre has an informal style that lets you get straight into the exploring and dice rolling action.
It may appear appear to be a small solo, but it's a living mini universe you're purchasing for your $3. Remember that solo games are a form of magic - it's a bargain considering that you're actually teleported to the Rainbow maze without need of batteries or a broadband connection or a Star Gate!