I introduced probability with a paper lunch bag and about 10 suckers in a variety of colours. (Make sure you have encough suckersfor the whole class at the end of the lesson!) We counted the suckers as they went into the bag and noted how many of each color we had right on the board for all to see. I asked one volunteer to come up (AND WOW WERE THEY EXCITED!). I asked what their favourite color of sucker would be. When they answered, I asked the class what is the probability the volunteer will get that colour of sucker? I told them they had to tell me the answer as a fraction of all the possibilities. There are ten suckers in the bag, so the probability has to be something out of ten. The students figured out that if there were three red ones and the kid wants red, the chances of him getting red are three out of ten. The kid reached in and pulled one out and the class cheered or said AW depending on whether it was the desired colour. I noted on the board which colour was drawn so it decreased the total of suckers available. Another volunteer and we kept going until the suckers were gone. The final draw was pretty simple, they knew what colour they would get and we discussed a probablity of 1 as being absolutely certain, and a probablity of 0 being absolutely impossible.
Kids bragged about the lesson to my principal. Not a bad lesson!