Let me open with one that a sister of mine came up with.

Ingredients: Everything for regular baking powder biscuits plus sharp cheddar cheese, mozzarella cheese and ham.

Follow the directions for making baking powder biscuits, except add in grated cheddar cheese to the dough. And then when you roll it, roll it thinner than usual. Cut out pieces in pairs, put pieces of sliced mozzarella cheese and ham between them, and pinch the biscuit together. Cook normally.

An excellent snack either hot or cold.

Cheers,
Ben