Calvados is French apple brandy (a fancy French version of applejack, if you know what that is). It's really nice to drink in the fall/winter; you can drink it neat and it tastes like apples. I use it in pate, as well.
But since I'm drinking down the more esoteric bottles in my bar, I'm drinking this.
1 1/2 oz Calvados
1 1/2 oz orange juice
3/4 oz Cointreau or triple sec
2 dashes Angostura bitters