As the region’s major theaters rebound from the dark nights of the pandemic, it’s nothing short of miraculous that its fringe scene — under-recognized and under-funded at the best of times — has found a way to keep the curtains rising. Operating on a wing and a prayer, these tiny theater troupes may be labors of semi-volunteer love, but they are, without doubt, the crazy, tinkling bells that keep a city’s culture alive, vibrant and just a whole lot more fun to explore.