Using "Read More" when post reaches vertical limit

Hello,
I tried doing a few searches, but couldn’t find an answer.

On this site http://hollywoodsalon.org/, I want to display the most recent event post. But because of my design, I’d like to keep the height of the containing div the same regardless of post link.

As a result, I’d like to display “Read More” if the content is longer than the containing div. Can someone tell me how best to do that?

Thank you!