Icing on the Cake

So my new hobby is.... taking a cake decorating class!
I've been waiting to do this for awhile now but I haven't so I decided now is the perfect time.  

My first class was last Thursday where we learned essentially how to put together a basic cake.  I had a list of supplies I would need which included some stuff I'm not so familiar with like Meringue Powder and high density shortening I bought food coloring gel and lots of boxes of cake mix.

So my assignment for the week is to cook 2- 8" cakes and stack them on top of each other, I can choose to put a filling in between the 2 layers or not.  I need to have it iced and ready to decorate for the next class.  We will be making a kids cake.  So I've been looking at cake ideas online and let me say they are either levels above my beginner abilities or they are just plain scary!
 We are just working with butter cream frosting so none of the fondant type stuff will work- just piping, which I have never done.
I need a theme but it has to be fairly simple, any ideas?? Really give me some ideas.

Dinosaurs? Obviously just designed on a round cake, I don't think I'm ready for shapes.  However my husband says he always wanted a dinosaur for his birthday cake, his birthday is in December... hmmm. He also read my blog so I have to make it a real surprise, but don't worry I have something cool planned.

Tropical ? The fish scales are made of fondant so I can't do it this time but I think but one day I will make this fish, I love the scales.

I'm excited to see how my first cake turns out.  And don't worry I will post it regardless of how awesome or how horrible it looks!

I'm pretty sure after this class I will be making cakes like this

and this.

I'll basically be the cake queen, haha, it's a joke. But I think I might be able to make something like this one

or this one

PS on a side note there are some cool people in my class so I'm learning a new hobby and making friends- bonus!