The environmental group Times Up has being doing great things for more than 20 years to promote a less toxic New York City by educating people about the impact we make through ordinary decisions like getting to work. To raise awareness and celebrate Halloween, wear your scariest costume and ride your bike with the Times Up Halloween Critical Mass from Union Square to their annual Halloween Party under the Williamsburg Bridge in Brooklyn. The ride is a demonstration of how terrifying the city streets may become without environmentally friendly transportation and community. Do something good, work off those Halloween-candy calories, and party with music from DJ Fake Money. How could Halloween be any better?

Fri., Oct. 26, 7 p.m., 2012