An Invention Convention is were hundreds of people come and share the inventions that they made. To enter an Invention Convention you will have to follow steps to make your own invention and build it as a working model. There are lots of invention challenges as well as local, state, and national contests held annually featuring many inventors and their inventions. Some schools hold these events, like the one I was in.  If you want to host your own Invention Convention talk to your teacher. All the details on how you can develop your own can be found on this site.  Check it out!
 

Who is this?  Rube Goldberg was a cartoonist for the "Chicago Tribune". He was famous for inventing additive designs. This was a machine, drawn as a cartoon, that showed a complicated contraption where one thing would connect to another and it all went together. He would draw a method where one thing would make something go and at the end it would catch or make something do a simple job.  His readers loved his cartoons and in 1948 he won a Pulitzer Prize.

Rube Goldberg was famous for bringing laughter to his readers by drawing cartoons.  Along with the pictures, he wrote ridiculous directions on how the machine worked.
 

Rube Goldberg walks in his sleep, strolls through a cactus field in his bare feet, and screams out an idea for self operating napkin: As you raise spoon of soup (A) to your mouth it pulls string (B), thereby jerking ladle (C) which throws cracker (D) past parrot (E). Parrot jumps after cracker and perch (F) tilts, upsetting seeds (G) into pail (H). Extra weight in pail pulls cord (I), which opens and lights automatic cigar lighter (J), setting off sky-rocket (K) which causes sickle (L) to cut string (M) and allow pendulum with attached napkin to swing back and forth thereby wiping off your chin. After the meal, substitute a harmonica for the napkin and you'll be able to entertain the guests with a little music.

For more opportunities to create Rube Goldberg additive designs check out this Rube Goldberg Machine Contest.