1 envelope of Knox Unflavored Gelain in a bowl, mix with hot water per directions,
add 1 envelope Kool-Aid brand drink mix (lemon lime is my fave)
and 1/4 - 1/2 cup Spenda (add up to 1 cup depending on how sweet you want it). The less splenda, the more tart it will be (which I like for some reason).
Mix it all until it dissolves then add the cold water per gelatin directions. Let set and eat with some heavy cream + splenda whipped together.