It only comes around once a year, but if you had the recipe, you could make it whenever you want. Consider it my St. Patrick's Day gift to you.

The Shamrock Shake has been offered by McDonald's restaurants around St. Patty's Day since 1970 (it even used to have its own mascot - Uncle O'Grimacey!). Like leprechauns, however, the frothy drink has developed somewhat of an elusive reputation, as it only pops up in select McDonald's venues throughout the country. Because of this, it has quite the cult following: the site ShamrockShake.com allows shake fans to record the locations where the drink has been spotted, as well as the date.

McDonald's Shamrock Shake Copycat Recipe
(makes 1 giant shake, or 2 generously sized shakes)

Ingredients:
3 cups good quality vanilla ice cream
1 3/4 cups 1% milk
1/2 teaspoon peppermint extract
Green food coloring, if desired

Directions:
Blend all ingredients in a blender until completely thick and smooth. Pour into glasses and serve!