Absent Mind, Clumsy Frame

Well, I had hoped to continue my Art of War for Writers series today, but, I have, with great skill, misplaced my copy of the book.  Sad, I know.

Yes, I am one of those people who can lose the glasses that are resting on the top of their heads.  In fact, I might have done that once or twice. I don't remember.

But all of this makes me wonder about making a character believable.  What if I wrote a character who is absentminded or loses things frequently or simply can't remember where he left them the last time he had them?

I've often wondered how a story would continue.  Sure, there are people like that in real life, and I sometimes count myself among them.  But in a story?  To keep everything relevant, he'd have to be losing the key thing he needs to beat the badguy or win the girl's heart or...whatever.  And then what would he do?

Talk about answering "What's the worst thing that could happen?"  What would a protagonist do from there?  I really don't know.

And I've wondered the same thing about clumsiness.  I, again, am a bit of a klutz, so I know what living it is like, but I've often thought it would hinder the action and story in a novel.  However, as I understand it, Bella Swan from the Twilight series is a major of clumsy.  Maybe I'll just have to read the books to find out how to write that.

What do you think?  How does one write a forgetful or clumsy character?  And how would that affect the plot?