Chocolate graham crackers have been rather elusive lately and it took numerous stops at different grocery stores to find a generic brand to purchase. You can always substitute plain graham crackers for a non-chocolate crust, and there are recipes online on how to make a chocolate graham crust using regular graham crackers and cocoa powder. If you can procure some Nabisco Famous Wafers, I've often made chocolate crusts using those, but the proportion of crumbs to butter may need to be tweaked.