As orange lovers have orange curaçao and its variations, lemon lovers have limoncello (aka lemoncello). This is a traditional Italian liqueur, often made at home. It's made by macerating (a fancy word for soaking) thinly sliced lemons or just the lemon peels in grain alcohol (vodka) for several weeks, straining and then adding a simple sweetening syrup.

The following recipes on this site use limoncello:

brandy, sweet vermouth, limoncello, peach bitters,