It’s in the humour category, but this thread is actually quite serious. Motorists talking on their phone are a serious threat to everyone around them.
If I find a driver using his phone at the head of the queue waiting at the lights, I position my bike in front of their car and wait for the lights to go green. When the inevitable blasts on the horn start up after the lights phase, I get off my bike, lay it on the ground and walk over to ask the driver to hang up his call. Can also be combined with method one, above.
If the driver ignores me (as is often the case) then I simply lift up the wiper blades on his windscreen, forcing him to pull over and get out to put them down again. It’s simple, not dangerous and doesn’t damage property in any way. For some reason, though – it really annoys them!