Paint the entire ceiling, including the pipes, a neutral color so the pipes blend in. If you want to make the pipes stand out as part of your decor, paint them a contrasting color.
Cover the entire ceiling with heavy fabric or thin plastic or bamboo blinds. You will need an assistant to hold the fabric in place while you use a nail gun to fasten it to the ceiling.
Install a dropped ceiling, if you have enough clearance. Suspend the ceiling and its frame low enough to cover all the pipes.
Build a soffit around the pipe with drywall. Then paint the entire ceiling to match.
Hang paper kites in interesting shapes and colors along the length of the pipe to conceal it.