Open a Make Meeting field inside colorbox
The easiest way to do this is through views. You can configure a view with an "Contextual Filter" of the node id to show and then configure it to show your makemeeting field here. Here's a screenshot of a view that worked for me (note the important parts are marked with arrows.



Then when I go to /meeting-popup/6 (where 6 is the id of a node with a meeting field) i see the following.



Then you can add a link to /meeting-popup/ on the nodes page using the lightbox-load class so it will showup in a popup.

Lastly you can theme the meeting-popup pages so that they only show the content and don't show any regions/sidebars, etc.

Alternatively you can have views make it into a "block" if you know of a good way to do it that way.