Becoming a parent tends to draw thick a line between the phases of one’s life, just as getting married separates people from the party-oriented pack with which they formerly ran. The new “Boogie Down” music and speaker series — from the minds who brought you the “civic health club” Warm Cookies of the Revolution — hopes to blur those lines in the name of fun and civic engagement. “I’ve been kicking around this idea for the last few years,” said Evan Weissman, who founded Warm Cookies, and who became a first-time dad six months ago.