Too many times
Hung up without saying a word. And hung up with a simple fsckoff.
I have behaved as if I didn't know what I was doing and kept them on the phone for around an hour and allowing them control over a VM before telling them I have been messing with computers since 1983 and asking them why they scam for a living.
I have allowed them into a VM, screen recorded everything and sent it to the UK police online fraud website: actionfraud.police.co.uk (I have incident numbers but never heard anything back)
I have even run Tcpview from sysinternals while they are viewing the vm and told them I am logging their IP address for a fraud report. Sometimes they just carry on trying to scam, other times they have disconnected immediately and hung up the phone.
My response depends on how busy or bored I am. I get many of these calls, occasionally 2 in a week. So much so that I have a dedicated Win7 VM setup just for this purpose.