Pulverize graham crackers in food processor until finely ground into crumbs (skip this step if starting with graham cracker crumbs).

Stir together graham cracker crumbs and sugars in a medium-sized bowl.  Add melted butter and use a fork to combine ingredients well until crumbs are all moistened.

Pour mixture into pie plate or springform pan.  Use the (clean!) bottom of a measuring cup to firmly pack crumbs into the bottom of the pan and (if using a pie pan) gently press up the sides.  Use your fingers to pack crumbs tightly into the sides of the pie pan.

If the crust needs to be pre-baked, bake on 350F (175C) for 10-13 minutes and allow to cool before filling. If using this crust as part of a different recipe, bake according to your recipe's instructions.  If this crust is for a no-bake recipe, refrigerate or freeze for 10-20 minutes before filling.