It took quite a while tinkering to eventually stumble on a solution.
The problem was that the builtin Mac wireless was not able to join a network (not for me anyways). But eventually I got the windows PC to join the Mac network. Here's how I did it.
Ensure there is no network with the ID that you want to use eg 'booger'. I then create a new network connection via 'system preferences'.

Choose 'network' then 'network port configurations'

then create a new network based on airport

now choose the new network

manually set the ip address

now open the 'network status'

now select the new network and press connect

now create a new wireless network

now press the 'network:' tab and 'create network' then set an ad-hoc network name and add a password

now you can connect to it via windows.
you could now ping from the Mac or Windows assuming you don't have a restrictive firewall.
