What do you get when you mix a whale-skeleton replica, a chess match and Argentine tango? Find out this weekend as local husband-and-wife collaborators Megan and Murray McMillan unveil Channelbone at White Flag Projects (4568 Manchester Avenue; 314-531-3442 or www.whiteflagprojects.org). The exhibition space will be swallowed by the large skeleton form, which houses the heart of the installation: a two-minute video of two chess players squaring off in an auditorium as tango dancers and veterans with spinal-cord injuries sashay through blue balloons. The McMillans recently returned from a stint as artists-in-residence in Barcelona, which may explain the inclusion of Latin dance in the installation's video. The rest is up to you to figure out. The exhibition is open on Friday from 7 to 10 p.m. and Saturday from noon to 5 p.m. (April 6 and 7). The event is free.