Get some packages of plastic Easter Eggs (the kind that split into halves to fill with candy) and some matching colored gumballs, jelly beans, skittles, ect to fill them. Get enough so that every student gets one or preferably, two each. Make a genotype and phenotype chart for them.
Example: PP= All purple egg + 4 purple jelly beans= Dominant Purebred pp= All pink egg + 4 pink jelly beans= Recessive Purebred Pp= Half pink and half purple egg +2 pink and 2 purple=Hybrid
You can do this with other colors to .
Then the kids did a Punnett Square to determine what the offspring would be from several possible crosses. The candies inside the eggs would be appropriate colors to match the results of their Punnett Square so that they could check themselves.