Experiments in Gingersnapping

Gingersnaps whisper mischievously to my experimental nature.  Classic spices like ginger, cloves, and cinnamon beg to be combined with citrus, heat, and sour.  As with most kitchen creations, I've never made a gingersnap recipe the same way twice.   This year's Christmas batch are based on the Joy of Cooking recipe, but include tangerine zest, lingonberry vinegar, and about 2 tablespoons of grated fresh ginger. 

What unique ingredients do you add to your gingersnaps and pepparkakor?