How to make him jealous at a party?

I'm going to a party with my ex whom I have not completely gotten over. I don't want to get back together because he treated me like crap at the end of our relationship. I just want him to see what he gave up by acting like a jackass. Guys: what would you hate to see your ex do at a party that would make you jealous?

Updates
+1 y
thanks! I did have a great time and ignored him and it worked. thanks to all!
How to make him jealous at a party?
Post Opinion