This boat-shaped Ahoi Citrus Juicer from Koziol is pretty cool. It comes in four different transparent colors, and I think it would be perfect for kids. The boat’s hold captures all the juice, and the pointed bow and stern act as a spout to easily pour juice without a mess.
I already have a very good citrus juicer that I like, but I think this one would be more fun for the kids. The handled squeezers can require a bit of coordination and strength to extract the juice.