/me does not care. Not sure about other folks though...do them a service :-p
In theory, a lot of residential routers (not provided by the ISP) will allow to set the sent MAC address via their web interface.
And on a full fledged Linux OS: ifconfig ethX hw ether MY:MA:CA:DD:RE:SS (or something like that, see man ifconfig)
I just did not say whether I have ever tried in real...