Mysterious Engine Noise
 

I have a 1999 Honda Civic LX which just rolled over 208,000 miles on the body and engine. I've noticed when the engine gets to about 3500 rpm, it makes a weird noise. Now this noise isn't very loud, but it's audible. I don't really know a better way to describe it other than the sound of water dripping, or like a ticking noise. It's really hard to explain. Does anyone know what this noise can be?

Make video of the sound. Maybe the valve clearance needs adjusting.