Stuck Option key

[ChaosShadow]

I sadly have no idea how I managed it, but I seem to have stuck my Option key in a permanent on position, which is making it impossible to type. Anything. At all.

I've verified that this seems to be the problem on the Keyboard Viewer, which, despite my best efforts, shows the Option key constantly in use. I've tried to do the obvious thing -- disable the Option key -- but to no avail.

Any suggestions would be appreciated. Thanks in advance.