and were tasked with making it as large as possible... what would your strategy be?  

push it to amsterdam and roll up all the coffee shops then smoke it

I would head straight to hollywood and pick up all the egos and implants!  OH!  giggidy giggidy

Well, first I'd roll up Osaka and then I'd roll my ball of horrible chaos all the way to Tokyo.

Then since it would be so large, I'd roll it across the ocean to America

And the rest is history

"push it to amsterdam and roll up all the coffee shops then smoke it
"

I would take my time since- beside your inevitable death- life has no time limits.

i would start in Seattel(where i live) and then roll it down the west coast till i hit Mexico

Well I'm torn between going to Mexico D.F (hihgest population city) or china. i think I'd hit china and roll over to India then see how large it is and take my options.

I figure Id start small, just roll it across the US to see what happens.  Then go into the pacific... then once I come out over in japan with a huge ball of whales and giant squids... and aliens.... that would be that.

Go to New York city and roll away.

Go to Texas. Everything is bigger in Texas.

Buy bigger pants.

I'd go to the bankrupted banks and pick up the $700 billion debt, then launch it off the planet

All I'd need to roll up is my penis.  =  /  That's larger than any katamari you can come up with!  = D

"I'd roll it around on a womens nude beach."