Here's a punch that we first had at a wedding, but since then have used it for Halloween parties.

Only uses three ingredients, too!

1 large can pineapple juice
1 package grape drink (pre-sweetened or unsweetened will work); can be sugar free
1 two-litre lemon-lime soda (may be sugar free, too)

Chill all ingredients.
Mix grape drink mix with the pineapple juice. Just before serving, add lemon-lime soda.

Looks gross, but tastes great!

Enjoy!