I purchased a brand new Raleigh Overtake hybrid bicycle last week. On my fourth ride, the pedals started clicking loudly and rapidly, not unlike the sound of winding an alarm clock. It only makes the sound when I'm sitting on it and pedaling. It occurs when pedaling in all gears, and seems to make the least noise when I'm pedaling really hard or pedaling VERY lightly. There's absolutely no feeling to the noise, it's simply a noise. I can't examine exactly where the sound emanates from because it doesn't make the sound unless I'm actually riding it. Turning the pedals by hand doesn't produce the sound.
The store will make any adjustments within 30 days of purchase, but I've already had to adjust the rear brakes and tightness of the front wheel myself, so I don't have much confidence in their abilities (it's a large chain hardware store).