I grow Tomatoes, peppers and herbs in containers every year. I also grow blueberries, raspberries, mulberries, gravers,citrus, dwarf peach and nectarines in containers.

If you are doing a veggie gardening project with kids from seeds, they expect almost instant gratification :-) Try things that germinate and put on growth fast - radishes, just about any type of salad greens, peas and beans. And all should be very easily grown in suitably sized containers.

Lettuce--fast and pretty.