Write a scene. Lois and Clark need to get from point A to point B. Or they need to stay in one spot for a long time (stakeout! or Kidnapped!). They're going to talk. What are they going to say? Pick a topic, any topic. Have Lois say something. Have Clark take what she says in the wrong way. (Or vice versa, usually vice versa works well... since Lois can be quite touchy.
) See where it takes you... correction... see where it takes THEM. Follow through on the conversation. If it turns fun (i.e. banter), post your results. If it doesn't, try again.
Groundhogs Day them until you get results. And by results, I mean Banter, not your characters reaching through the screen and strangling you. (That would be another thread entirely... and probably a fun one for a different reason.)
For some strange reason, some of my best banter comes from these scenes where I just don't know where to end it. I guess, most people would cut the scene and add a transition. I follow them along, wondering how did they get onto the topic of naming all 7 of Snow White's friends, instead of starting them already in the conversation.
Have fun!