Use Ernie! He's a rather cliche old man that my friend and I invented as a plot catalyst... he basically pops in when you're stuck to rant about doom and the apocalypse and hopefully make something happen.

Alternatively just do something random and hope for the best.

Or you could ask your characters what they want to do, and do it, and then hope for the best.

Sometimes just taking a break and writing a nonsense chapter wherein you kill everyone you don't like and think up glorified endings for everyone you do like can help you think of something. 

I have that problem sometimes, too. What I do is then just start writing the middle, if I already know what happens. Once I get more comfortable with the story and the characters, I can usually write a beginning/ending. Also if I write the middle first I'll sometimes get a brilliant idea for a scene to jump-start the story. Good luck!

P.S. TNO - I love the idea of a character that you use whenever.