Check out this post for a download link to run the dungeon yourself - it's suitable for parties of level 2 to 4.
I've been DMing for 8 years and I've never actually run a proper dungeon, so recently I decided I'd try my hand at it. I didn't want to run just a series of rooms with fights and treasure in them, so I figured I'd need one or two unique mechanics that run through the whole dungeon and tie everything together, so that each room feels like part of one big encounter rather than isolated battles or puzzles.
I settled on a maze with a phasing invulnerable guardian. That probably sounds a lot scarier than it actually was, though I'll admit that it was in fact pretty scary.