New to the forums but long time CC user here. I'm designing a site where the client would like to have a pop-up ad on the homepage, never come across this before. Anyone know of a way to do this with any of the CC software?

Hi, Guess I will jump in here...

There are a couple things that may work, but generally I see that "pop-ups" are discouraged, and many users block them from working (browswer pluggins/Vista addons and such). The only nice way for a pop-up to be placed on a page is with a link that the user has a choice like "click here for more information", and when the user clicks, a "pop-up" style window opens.
If you are using the HTML editor, there is a DHTML tool that can be used (under "insert/DHTML ITEMS/ DHTML Window Designer). It can help you to created a dhtml and javascript pop-up style window that will work for anyone with java turned on (default setting) on their web browser. It also does not trigger most pop-up blockers since it is user innitiated.