I made these recently for a friend of mine's birthday who likes A) Mexican Food and B) Lemon 'Stuff.' These would be cute for a Fiesta Themed party. I made a key lime/lemon cookie/cake ball that turned out to be really delicious (said the girl who doesn't like lemon-which is how I know it's tasty).
I bought some lemon flavored cookies (you can buy the kind with the cream in the the middle, this pretty much works the same as oreo truffles). I crushed up 1 cup of the cookies using a blender (doesn't have to be totally sandy, but pretty small chunks), and then I mixed in half a thing of softened cream cheese and about 1/4 t. lime flavoring.
I mixed it all together...
Then I rolled it into balls (this made 10 balls, so use the whole bar of cream cheese would have made 20). I put these balls into the fridge to harden a bit (so it would be easy to roll in melted chocolate, I left it over night, but an hour or so would have done the trick).
I added these to a little margarita glass I bought at the dollar store.