Make the default background color a medium gray. We are also changing the navbar back to the default so adjust the 'brand' link colors to match.
Put the copyright in the footer into its own 'row'.
Make the jumbotron background green with black text. Adjust the image just slightly to remove some of the lighter gray/white from it so it doesn't look strange on the green background.
Make the sections 450px minimum in height. Readd the upcoming meetings section on the front page the bootstrap way.