Cracking Grains

Hey all: another question from the eternal newb...
It's brew-day once again, and I have all the materials for a rye beer. The only problem is that I forgot to crack the grains while I was at my LHBS. I think I can crush it with a rolling pin (either the marbel one for pastry or my trusty wood one), but I was wondering if anyone has some tips on how crushed it should be, and how do I determine how crushed it is?
I was thinking of transfering the grains into zip-locks to make a thin layer, and then rolling them in batches. Sound reasonable?

I'd head back to your LHBS and have them properly crushed.

I have done it with a rolling pin and it will dent a wood one. As to how cracked it should be, you need for pretty much every kernal to be broken open.If you've never seen cracked grains perhaps you could google a picture,or maybe there's a U-tube video out there. But,if it isn't far at all to your LHBS maybe you do want to go back there.If you're at all like me youmight want to leave your wallet at home though

I personally have never done it but from what I have read, you want to crack the grains open but not pulverize them. You dont want to turn them into flour. Where in Philly are you located and where do you get your ingredients? I live in N.E.Philly and I shop at Barrys and at Wine, Barley Hopps.

I do most of my shopping at Barry's. He was closed when I was last shopping, so I bought this batch of LME/DME/grain from a guy in center city. I was in a hurry, and didn't even think about crushing the grain at the time.
As for my location: I'm in Kensington, just North or Fishtown and South of Port Richmond.

The place in Center City is HomeSweet Homebrew. Ive never been there but I have been to Barrys, he is usually opened on Saturdays. I know Kensington very well, I grew up there, on Lee St near Front and Huntingdon.

How many lbs of grain are we talking? 8? 12? If so, I can't imagine doing them well enough with a rolling pin. Even in small batches it will take longer than driving to and from LHS. Although the mill at Home Sweet Homebrew is pretty slow itself.
I'm in Lansdowne, on the SW side of Philly. HSH is very close but I think I prefer Brew Your Own Beer in Havertown.