[blahaj]

I found out today that the location header of an HTTP redirect can be a tel:+ URI and phone's will actually ask you whether you want to call that number.

[mediumdeviation]

Links can have that as their href and it will also work as you'd expect. It's the telephone equivalent of the more well-known mailto: scheme

[econ]

Now we should add a ?message= query string to be read out loud in the users voice.

[Aachen]

Did you know that you can assign arbitrary programs (protocol handlers) to arbitrary protocols?