How to stop a phone from ringing without rejecting the call? Sometimes I don't want to take a call, but I don't want him to know that. So I left the phone be until it stops, so it would appear that I'm away from phone or something and I miss the call. Can I silence the ringing tone and the vibration while doing that?

Info: My phone is Galaxy S
I suspect this is very much device dependent, but on the HTC Desire HD, you can press the physical volume down button to silence the ringtone whilst allowing the call to continue.