Cirque Éloize (pronounced El-Waz) is in town. The Montreal-based troupe of acrobats, jugglers and rope climbers began a 21⁄2-week engagement at the theater on Wednesday. During the day, Cirque performers and associates are teaching techniques to teens and adults in weeklong summer camps. Aspiring aerialists between 9 and 14 will finish their lessons on Friday; next week, teens 15 through 18 will be on wires and swings. On Aug. 19, a week of adult day classes will begin. Pushing limits “It can push your limits in a noncompetitive environment and you can be creative, be physical, think for yourself,” said veteran performer Nicolas Boivin, 31, of Montreal, who along with Cirque acrobat Henriet, 28, of Sweden and Cirque coach Shannon Maguire, 26, of St. Paul, Minn., are instructing students.