In a 1- or 2-cup glass measure stir together boiling water and gelatin until gelatin dissolves. Pour into a blender container. Add undrained pineapple and banana chunks. Cover and blend until smooth.
Pour a scant 1/2 cup of the fruit mixture into each of eight 5- to 6-ounce paper or plastic drink cups. (Or pour a scant 1/3 cup into each of twelve 3-ounce cups.) Cover each cup with foil. Using the tip of a knife, make a small hole in the foil over each cup. Insert a wooden stick into the cup through the hole. Freeze about 6 hours or until firm.
To serve, quickly dip the cups in warm water to slightly soften fruit mixture. Remove foil and loosen sides of pops from drink cups. Tear off the paper. Makes 8 to 12 pops.