In a large container, such as a 1 gallon water jug, put in 1/3 of the bottle of rum, 1/3 of the vodka, 1/3 of the triple sec, and 1/3 of the sour mix. Add the grapes in to make sure they soak up some of the alcohol. Let it sit for a while or continue combining, depending on how strong you want your grapes. Combine the rest with the cranberry juice and the sprite.
It should be a dark red color that's got fizz to it, but shouldn't be completely diluted. You're ready to go!