“The Little Mermaid”: 8 p.m. at Greenhouse Theater Center, 2257 N. Lincoln Ave., New Buffalo, Michigan. (866) 494-6371. fourwindscasino.com. The Purple Xperience: 7 p-m. At Hobart Art Theater, 154 W. Chicago St., Valparaiso. ($39-$41. (773) 404-7736. greenhousetheater.org.