We had to do a treasure hunt, which consisted of 3 levels, a puzzle, an animation and a movie, and everyone did pirates/soldiers etc and I did mine on Chemistry. I did the puzzle on Carbon, animation on Oxygen and now I need to make the movie. I called the hunt ''Element Quest'' and the story behind is that a young chemist wants to get a Chemistry Snobel Prize (I couldn't do Nobel due to copyrights) and in order to get it, he needs to complete my ''Element Quest!''
Helium is the least interesting, it's basically inert, so not much you can do with it, besides getting a high-pitched voice.
Fluorine is the most fun, has the highest electro negativity, and very reactive to the point where you can get some weird combinations as they just latch on to each electron.
Try Helium - super fluid at close temperatures to 1-2 kelvin Mercury - Pretty cool liquid metal Hydrogen - Stars and forms any other element, simplest element and our universe is rich in it. Carbon - Diamond, graphite, carbon based organisms...oragnic chemistry. Well these are my favourite.