I'm barely old enough to remember the days when Adobe fought to keep the specs of its Postscript type 1 fonts a secret, so it always makes me smile when Adobe releases a new font designed that's freely available under an open license. Following up on the launch of Source Sans Pro last month, Adobe has now released a monospaced font in the same family called Source Code Pro. While monospaced fonts aren't in common usage on the web or in apps, they're perfect for environments where vertical spacing matters, like development environments and IRC apps.
Source Code Pro available as part of the OFL, that's the Open Font License, 1.1