Catholic Underground is an apostolate of our friends at the Franciscian Friars of the Renewal, C.F.R.'s.  Their original location in NYC is held the 1st Saturday of every month (Sept thru May) from 7:30pm until 10:30pm.  There are now locations throughout the NY/NJ/CT tristate area in Somerville, NJ / CT / Hopewell Junction, NY and other locations throughout the USA and Europe such as Chicago, LA, Philly, London, etc.  It's a beautiful evening of Adoration and New Evangelization showcasing Catholic artists and culture, all wrapped in prayer.  Check out the following sites for futher info:

http://catholicunderground.net/

http://www.facebook.com/catholicundergroundsomervillenj

http://www.facebook.com/pages/Catholic-Underground-North-St-Columba-Parish-Hopewell-Junction-NY/127004496083

http://www.catholicundergroundct.com/

http://www.catholicundergroundla.com/