I was working on a project. The tinyduino had been plugged in to usb for 30 minutes. I unplugged my usb cord to do something. When I plugged it back in the stack immediately started smoking and smelling toxic. The processor shield gets really hot. I can still upload code to the stack but I quickly have to power down as it gets hot. I have examined all ports and see no bent pins or such.

Shields in the stack bottom to top were:
Processor,
USB interface,
LCD Screen.

That's pretty unusual that it still works, but I would advise you don't continue using it- please send an email to info@tinycircuits.com so we can handle the issue and hopefully have you send that board back so we can look at it.

Thanks,
Ben