At 5th grade, I recall using science topics to discuss statistics and probability.
Using a color spinner and plotting results is one way of doing this simply.
Another way is to use a 'penny' box to simulate a Gaussian distribution or decay curve and explain that the variance is random, etc. and can be predicted by using statistics.
In other words, we looked for real-world applications of simple statistical models-- dice (esp. the more interesting RPG dice if you want a challenge), coins, spinners, etc.
The mathematical relationships are a pretty organic extension of all of that.
