So I just put 2 + 2 together:
 
Bioware likes slamming asteroids for the finale's of their games.
Reapers are invading in ME3.
Ergo, you will defeat the Reapers by slamming a giant asteroid in them.  
Go one level deeper and it's multiple asteroids.
 

Bacon in the pan!

That's idiotic; you can't just use the same trick like that twice. 
... 
Obviously as Shepard you'll cause all the Reapers to crash into Asteroids, Lemmings style.

That's brilliant!

Bacon in the pan, that is. The rest is rubbish.

(just kidding)

No man, you don't get it. The Reapers are asteroids! That's the twist!

No man, you don't get it. The Reapers are asteroids! That's the twist!

You guys, ME3 is actually just a cover, when you go to load the game you're just gonna play Asteroids!

@DoctorTran:  The whole robot squid invasion force is just a trick. They are already all around us, but have no means of attack. Once we strap rocket engines to them in an attempt to fight off the perceived threat of space calamari they will be empowered and send themselves hurling at all major systems. The frequency of throwing big rocks at stuff in the Mass Effect universe is a side effect of the Reaper's indoctrination powers constantly feeding the subtle suggestion of this grand plan.

That's brilliant!

Bacon in the pan, that is. The rest is rubbish.

(just kidding)

" You guys, ME3 is actually just a cover, when you go to load the game you're just gonna play Asteroids! "

" So I just put 2 + 2 together:
 
Bioware likes slamming asteroids for the finale's of their games.
Reapers are invading in ME3.
Ergo, you will defeat the Reapers by slamming a giant asteroid in them.  
Go one level deeper and it's multiple asteroids.   Bacon in the pan! "

You're going to need a lot of asteroids.

"Bioware likes slamming asteroids for the finale's of their games."

" Deeper. "

" You're going to need a lot of asteroids. "

GENIUS. You know, that isn't the most far out thing one could think of.

If it's going to be about asteroids, then I guarantee you'll have to fuck around mining them to find the right one to chuck at the Reapers.  So, 7-8 hours of mining, 1-2 hours of endgame. Sweet!

Perhaps the ending to ME3 will have you defend the earth in a tiny spacecraft like the video game "Asteroids" similar to what Fry did in Futurama.