I'm using AutoHotKey on Windows. Not only for this, but for other things, as well.

For example (<^>! means the AltGr key):

  <^>!4::Send „
  <^>!5::Send “
  <^>!2::Send ‚
  <^>!3::Send ‘
  <^>!+6::Send “
  <^>!+7::Send ”
  <^>!+8::Send ‘
  <^>!+9::Send ’
  <^>!-::Send –
  <^>!.::Send …

Also to use Caps Lock as another Control key:

  Capslock::Ctrl

Or make windows stay on top of others, if even they lose focus:

  <^>!t::Winset, Alwaysontop, TOGGLE, A