ICABoston’s newest museum, the Institute of Contemporary Art, opens its doors gratis for one evening a week only in December through Target’s sponsorship of Free Thursday Nights.  Home to a vast array of works from emerging and established artists, the ICA offers patrons an assemblage of outstanding works in all media. The waterfront museum, designed by award-winning architects Diller Scofidio + Renfro, is, at once, contemplative and dynamic, mirroring the spirit and sense of the installations housed within.