I need some fast, easy cheek art designs

I have a really big gig next month and I have hired my little sister to be my assistant for the day. She doesn't really have much experience face painting, so I figured I could just set her up with some easy cheek art designs. She can do them, and I can do the larger, more detailed designs.
I've already taught her a few basics-butterfly, ladybug, dragonfly, and flower- but I need to get her going with some boy designs. The only problem is that I don't really know any boy cheek art designs, so I need some ideas. Pictures would be great as well.

Thanks in advance!

I don't have any pictures sadly... but here a few suggestions that I have done for squirmy impatient little boys.
A rocket.... sometimes with a planet and some stars.
A train..... doesn't have to be Thomas
A spider..... they seem to like creepy.
A snake...... I do the one with the rainbow cake swipes over cheeks and forehead - really fast and easy.
An omnitrix...... this is the watch thingy Ben ten wears...... don't know how popular Ben 10 is outside Australia.
A scar..... boys like to look like they have been fighting....funny about that.
The transformer logo..... it's just a stylized transformer head.
A skate board......... really simple but surprisingly popular.
Sometimes I do a couple of square metal looking plates with rivots to look like he's part android/robot.

That's all I can think of off the top of my head.
Hope that helps.

Thanks for the ideas, guys!
Tash, a rocket is perfect. My sister is doodling those all of the time. I will definitely add that to the list.
So far I am thinking that, a skull, a race car, and a snake. I will make her practice those for a while and then maybe add a few.

The Lizard and (burning) skull are the most popular among boys.

I would recommend Roberta Madella's cheek art book. It has a lot of ideas and photos. It could be a bit more dazzling, but would give you what you need quickly and in a book form. Lot's of good work here too of course, but sometimes it is good to have the books. Just a thought!

Here are some quick boy designs I've done, they are all either on me or during a gig, so forgive the poor photo quality of a couple of them!

ooh, I love the baseball. I will have to add that to the list.
My sister is really excited because the lady is paying an extra $100 for me to bring an assistant. For a seventeen year old at a three hour gig, that is pretty good.