An interactive demonstration of Conventional Current vs the Flow of Electrons (and a race)
Some obstacles to make a circuit (course).
Split the Cubs into two teams. One team are at the Positive end of the "battery". The other at the negative end.
Arrange a course, with two rope marking the wires/tracks of the circuit from the battery to a cub or leader half way around holding a torch. Have someone else holding the two ropes part way around the circuit to act as a "switch" (Or holding one end and then touching the person holding the torch while they hold the other end).
When the leader holding the ropes connects them together and shouts "ON!" the cubs have to run from the positive battery to the negative (Conventional Current) while the other team run from the negative to the positive (flow of Electrons). When the cubs are moving the leader holding the torch turns it ON.
When the leader with the rope splits the ropes and shouts "OFF!" then the cubs have to stand still and the torch is switched off.
When all of the cubs have reached the other end of the battery, repeat as often as required. You could also "Change the polarity" of the battery and explain what happens.
Explain to the cubs that this is a basic circuit but that not all will work in the same way (they don't like the reversing of polarity for example).