It’s finally cool enough that I don’t want to pass out from just thinking about working out, and the free ballet barre class happening on Monday night on Pier 2 at Brooklyn Bridge Park sounds like a pretty nice way to ease back in. Engage all your core muscles and get your heart pumping en plein air at 7pm (registration starts at 6:30pm). For a less ambitious and more sedentary start to your week, head instead to the Brooklyn Historical Society for a special screening of the 80s classic Bill & Ted’s Excellent Adventure at 6:30pm. Newsday film critic Rafer Guzman and Slate’s Kristen Meinzer will be on hand to introduce the film, which is being shown as part of BHS’s Hollywood Does History. . . Poorly series. The event is free but you should register in advance.