Hmm - I think this is why it is important to have a big pool of people. We have a League which consists of 15 players or so, but every 2 weeks we play a 6 player, single table game (you can see it on the home page calendar out of interest). This means that we rarely battle to find our 6 players.
Every couple of months we open up the league and let someone knew join (we play amongst good friends for fun). This keeps it interesting...
This is indeed a good principle, because you can do whatever you can to keep a poker night interesting, but without the right people you efforts can be worthless, I'm afraid.