It's time for me to upgrade my cell phone; and I'd like to be able to write .Net applications and run them on my phone.

The biggest thing I want to play with is the GPS functionality; so that is a must - but I'd really like to be able to control as much of the phone as possible. Like being able to intercept real events (like an incoming call) and flagging them as handled to prevent the phone from ringing if it is from a particular caller, or if the GPS device says my location is in a particular region.

So yeah, the more things I can do through code, the happier I'd be. I don't plan to deploy any of these things; just little toy apps for own personal use.

Could anyone recommend some options to me?