Trim rhubarb and cut into 1/2-in. pieces. In a large bowl, mix rhubarb with sugar, tapioca, and marmalade and let sit 15 minutes. Divide rhubarb and juices among eight 1-cup ramekins and set ramekins on a baking sheet.
Bake rhubarb until soft but still holding its shape, about 30 minutes.
Transfer to a rack and let cool a little.
Meanwhile, scoop out 8 small ice cream balls and set on baking sheet in freezer. Freeze at least 15 minutes, or until quite hard. Put almonds in a bowl and coat each ball with nuts; then put the balls back in freezer until ready to serve.
Serve rhubarb warm or at room temperature, each ramekin topped with an ice cream ball.
