There are a few things that make brunch spectacular, and unlimited mimosas is only the tip of the poached egg. On April 27, a group called Rally Downtown, created in the wake of Superstorm Sandy to help ailing businesses recover and non-profits thrive, has organized a brunch to end all brunches. Greenpoint and Williamsburg restaurants including Anella, Selamat Pagi, Brooklyn Label, Cafecita Bogota, Ovenly, Mable’s Smokehouse, Action Burger and Osteria Il Paiolo are gathering in the immense backyard of t.b.d. for a three-hour, all-you-can-eat brunch with bottomless mimosas. Tickets are $30 for one, $50 for two and help support the Greenpoint Reformed Church Food Pantry and The LAMP.