Alrighty then:
If Rossi wins the next two races that's 274 points.
If Hayden gets 2nd in the next two races, that's 276 points & the Championship.
If Rossi gets 2nd in the next two races, that's 264 points.
If Hayden gets 3rd in the next two races, that's 268 points & the Championship.
If Rossi gets 3rd in the next two races, that's 256 points.
If Hayden gets 4th in the next two races, that's 262 points and the Championship.
If Rossi gets a 2nd and a 3rd, that's 260 points.
If Hayden gets 4th in the next two races, that's 262 points & the Championship.
If Rossi gets a 2nd and 3rd, that's 260 points.
If Hayden gets a 2nd and 3rd, that's 272 points & the Champioship.
If Rossi gets a 5th and a 3rd, that's 251 points.
If Hayden gets a 5th and a 3rd, that's 263 points & the Championship.
If Hayden gets 4th in the next two races and Rossi gets 2nd in the next two races, Rossi wins the Championship by 2 points.
If Melandri wins the next two races, that's 259 points
If Capirossi wins the next two races, that's 255 points
If Pedrosa wins the next two races, that's 252 points.
If Hayden DNF's, it's over.

Okay, I confess, I didn't do the math. My Mom and I where having a discussion of the possibilities and this is what she came up with.... :-*