Photoshop takes time and patience. Exploring all the tools available in Photoshop could take an eternity. Getting the special effect you want takes practice and skill.
When you just want to have some fun and don't have a lot of time, I have one solution for you.
Fun Photo Box is a site that lets you upload any image, plaster it on a billboard, on money, newspaper headlines, or even with famous people.
Here are just a couple examples of my photo that I uploaded.
Of course this will never replace Photoshop and all the things I can do with it.
However, what a neat tool just to have some fun!
Here is the link to the site: http://www.funphotobox.com/