I haven't done anything that specifically relates to your situation, but improving the visibility and quality of physics instruction is something that I and many others here do, so maybe there's sufficient overlap.
I *really* like your idea of 'Physics Night'- and it may be easier if you make it 'Science Night' so that the other science teachers will help out, and open it up for as many grade levels as possible.
One suggestion- instead of trying to 'lure folks away from biology and over to physics', a better strategy may be to 'go to them'- show students who are interested in biology how many biological processes can be understood in terms of the relevant physics: blood pressure and the cardiovascular system in terms of fluid flow and partial pressures, for example. Another example- photosynthesis is an incredibly complex process that involves (AFAIK) quantum mechanics to understand.
In any case, please share any tips and successes with us- good luck!