When the hiring manager asks you if you have more questions during an interview, take this as an opportunity to help him visualize you at the job. In a thread on Reddit, some commenters suggest asking questions like "What is one thing I could accomplish in my first six months here that would have the most impact?" and "If I were chosen for this position, what would a regular day at work look like for me?"
This helps the interviewer form a mental image of you being part of their team and company, which can make you more memorable. However, be sure to keep it subtle, and avoid direct and aggressive questions like "When do I start?" or you might turn your interviewers off.