Are there a better ways to crush biscuits/cookies than a rolling pin?
Generally, I've only heard of the plastic bag or the food processor.

I have seen people who just bash the packet of biscuits on the kitchen top. Jamie Oliver likes to do that with slabs of chocolate!

Otherwise use a heavy duty snack-lock bag or else wrap the plastic bag in a tea towel.

It helps to have a small hole for the air to escape.