How about some applied physics and engineering being added to the Lego line of products? This kit featuring a dynamic marble run and a bunch of dominoes by Christian Bechinie would be fun to build, looks amazing in motion and has hundreds of elements that could be reused in other machines.
With Lego Ideas, the populous can vote on what sets they want Lego to produce. After a project reaches 10,000 votes, Lego reviews all the qualifying projects for that particular period, figures out which ones are viable products and those get made and put into stores.
Of course, building with Lego always fuels the imagination, but it can be a powerful tool in education as well. You can support this particular project here. Be sure to watch the video of it in action below.