Guys help me be a vindictive female

[ilovemyglo]

Okay, this is childish and rude, but I am asking for the help of the men on GC...
I am going to my homecoming this weekend and a few of my exboyfriends will be there. There is one in particular that I really want to make say "Damn I screwed up". So what should I do? I mean I am not planning on hooking up with one of his fraternity brothers, but should I speak, avoid, make eye contact wave and walk on? What would get to you?
Also, it's kind of chilly so ladies I need help on what to wear. Pants and nice top? Dress and deal with the cold? What to do!
I have an alumnae brunch with the sorority and then we go tailgating and then dinner... so I need something I can wear to all three!
Thanks everyone!
Sarah