We have the Noah's Ark Little People Play set that is a lot of fun to use for this theme. To tell the story I used the set. I hid the animals around the living room. When it came time for Noah to gather all the animals I had my son find the animals and put them in the ark. After all the animals were gathered we put Noah and his wife in the ark. Then we swayed the ark back and forth and used our hands to pretend it was raining. Then when it was time we let all the animals out and my son found them new "homes". Of course, he wanted a turn hiding the animals and telling the story too.
I also read Jan Brett's "On Noah's Ark" board book. It has great illustrations and is not very wordy so it easily keeps small children engaged in the story.
Our main source for the day was from Living Intentionally. She has a huge Noah's Ark pack that we enjoyed several activities from.
Here my son is drawing a picture of a penguin.
This link has several coloring pages like the one below.
You can find this printable book and more Noah's Ark activities here.