Ghostbusters (PG, 105 min.) Memphians this week have three opportunities to see the 1984 supernatural comedy on a really big screen. On Saturday and Sunday, Slimer will materialize on the IMAX-sized venue at the Pink Palace; then on Thursday, he will float on over to the "Chimes Square" courtyard at Overton Square for a free outdoor showing. 4 p.m. Saturday and Sunday, CTI 3D Giant Theater, Memphis Pink Palace Museum, and 7 p.m. Thursday, Overton Square courtyard. For more information, visit memphismuseums.org or overtonsquare.com.