You can find the tried and true recipe in the book, The Hungry Scientist Handbook, though we're guessing any lemonade recipe will suffice. Since the dry ice turns to Co2 (in gas formation) as it sublimates or thaws, it's best to use a straw when consuming a beverage which has a chunk of dry ice in it. The air at the top of the glass will be displaced and a straw will keep your lungs air free and your tummy full of chilled lemonade!
Dry ice will also cause the appearance of bubbles being rapidly released on the surface. It's not boiling, but is a simple sign/side effect of the solid-gas change taking place. Just make sure you secure a block of dry ice before the party starts and chip it into pieces small enough to fit into a glass. Make sure to wear protective gloves and possibly eyewear. Enjoy!
• Related: Flickr Find: Smoked Lemons & Lemonade