Sometimes when I put my hand over my kneecap and move my knee slowly, I can feel it slightly creaking. You can’t hear it, and it doesn’t hurt. I’m a student so that should give an indication of my age. I do play a lot of sport although I don’t know if that affects it at all.
Thanks.
Sounds to me (in my completely uninformed opinion) that you have a lack of synovial fluid in your knee. As I understand, the synovial fluid “lubricates” the joint and is released as the joint moves. A simple series of 'kicking" (slowly moving your knee as far as you can) should help (although you may have to do it 20 or so times).
You may have mild arthritis. My diagnosis for knee problems changed from “growing pains” to “arthritis” between my early teens and age 21, and my knees do that too; I injured my knee badly when I was 12 or so, and my mother was also diagnosed quite young, so it didn’t surprise anyone when I finally got the verdict. Kicking as Chairman Pow said will often relieve the sensation - I usually put the side of a hand just above the knee in question while kicking it until it pops and feels better. If it does end up hurting, a knee brace will help even more.
The really weird thing about the creakiness you feel is that other people can feel this too! When I was still in my late teens my little brother wanted to know what I was doing, and I told him I was trying to figure out if my knee just felt creaky or if I could just hear it (he didn’t hear anything, but I could), so he asked if he could see. Then he pulled his hand away like he was burned saying it felt really creepy. 
Thanks for your input guys, it sounds to me like it’s probably the synovial fluid one, 'cause ‘kicking’ my leg does make it better. I also asked my friend to see if it really was creaky but when she did, she thought it was really freaky.
I had the same thing happen from when I was really young (like 8 years old) until somewhere in my early 20’s. It just went away over time and never caused any real problems. Other people could even hear mine if they listened closely. At 31, it is completely gone and I haven’t thought about it in years.
Creaking in the knee is normal. If it is the only symptom there is probably nothing wrong. It’s called “crepitus”.
Dr_Pap MD
On a related note, hold your arm up so your wrist is near your ear, clench your fist and rotate your wrist, as if you were using a screwdriver. Grind grind scrape :eek:
[sub]Or is that just me?[/sub]
I tried that, nothing.
Or maybe the ringing in my ears hid the noise of my joints grinding 
