Yours faithfully,
Mac Packard.
Now this would have had me immediately suspicious... besides, anything to do with Mac (Steve Jobs) is patented, so the prize money would be technically his and you'd probably get sued for trying to spend it. 
I mean, you'd think they'd come up with a better, more convincing name - like Gates Packard, or Linux Hewlett, even Hewlett Windows - cos Mac Packard just ain't cosher. 