Just past Oyafukodori towards the ocean, you might notice a pungent combination of butane gas and burning pork fat. Most likely that is coming from Nagahama, a street with a huge collection of Hakata ramen stalls and small restaurants. Hakata people take great pride in their ramen, which is based on a pork soup broth and noodles, and often not much more. Along the Naka River in Nakasu at night you will also see a long series of stalls called yatai, but Nagahama is more where the action is at (though they can't compete with the river and bright lights).
Here's a look at the Nakasu Yatai:
