I lead an international team of high level amateurs under the banner of Spectrashift.com and we are in the process of building a telescope system that can discover a new extrasolar planet. The field is relatively new with the first exoplanet discovery in the mid 1990's and none have ever been discovered by non-professionals.
In 1995 the professional astronomers Marcy and Butler discovered a planet around the star Tau Bootis. In 2000 our team were the first amateurs to detect the wobble of the star caused by its planet and only 5 years behind the pros. We are now constructing 1 meter telescope which will probe deep enough to measure the radial velocities of 8th magnitude stars where the new planets are being discovered.
I sponsor the most popular exhibit at the Adler Planetarium. Its called Make an Impact and it uses hollow paintballs fired at high speed into powder to create a miniature crater. The gun goes off every few minutes and the kids just love it!