I recently stumbled upon this interesting opportunity to pitch your novel on Twitter: #PitMad. It's a twelve-hour window in which writers can post a 140-word pitch, which will be perused by agents and editors.
It's a quarterly event, and the next dates have already been posted:
June 4, 2015
September 10, 2015
December 4, 2015
I'm sooo going to try to get my manuscript polished by June 4th. ;-)