cinder block

I need all of my precious stage space for our production of Cabaret, as the pit will be on stage. So I'm going to keep our back curtain open (we are at a school), and expose the back (black) cinder block wall and music room door. I want the back wall to look like old brick wall with a top edge...

Have to create realistic painted cinder block walls - anyone have a brilliant idea? I've seen a technique that involves troweling on a thin layer of drywall mud over your hard-covered flat and, stippling to add texture, then scraping out grout lines. this seems time consuming -- I'd love to...