I was recently asked by someone I very much respect to address "the" question. So I started to write the answer in a post... about five times without any luck. The "Why does a 20-something join a Reform Congregation" question.
"Dedication;" the joyous eight-day celebration during which Jews commemorate the victory of the Macabees over the armies of Syria in 165 B.C.E. and the subsequent liberation and rededication of the Temple in Jerusalem.