This is a "yet another modal dialog JQuery plugin with lightbox effects", created by Michael Mahemoff at Osmosoft with the following aims:
Progammatic invocation. This isn't one of those magic genie libraries that inspects the DOM on load and makes everything clickable if its class is "lightbox"; it requires code to trigger the modal dialog appearance. (Few libraries sadly offer such functionality.)
Small in size (1.8KB last I checked; compressed to 1.3KB).
One file to install - all styling in Javascript by default. (Maybe stylesheet support later, but for now, I just want to ensure it's easy to get it up and running by including a single JS file.)
Easy to use: $.modal.show("message");
Dismiss the dialog with keyboard shortcut or by clicking outside the dialog.
It was initally built for TiddlyDocs, but could be used in any JQuery app.