Newsround's brain boggling competition to get you guys inventing - you too can be an absolute genius - is hotting up and entries are coming in thick and fast.
But if you're still having trouble trying to think of something to invent Joe's here to help.
To give you some inspiration he's been checking out some of the inventions that have rocked the world.
Watch Joe's report on photography and remember - say cheese!
Why not give inventing a go yourself and take part in Newsround's Inventions Competition?