Artist Aaron Gach's "Tactical Ice Cream Unit"was created last fall under activist auspices, made to dispense progressive propaganda and encourage dialogue about the military. But with the Big Brother bravado came food for thought: specifically, popsicles from the Tropicana ice-cream shop on Southwest Boulevard. The kids -- well, they ate it up. At the project's opening reception at Grand Arts, the SWAT van/ice-cream truck teemed with children who were oblivious to the message but had loads of fun with the 360-degree video monitors. And that, friends, was a helluva lot more refreshing than the frosty treats.