I don't think any chapters at my school invite alumni to formal- I'd never heard of that until I saw some references to it on here. My alum chapter has talked about hosting a semi-formal event (such as a wine & cheese) for alums & collegians. Don't know if we'll pull it off, though.
I'm actually going to a formal event in a couple of weeks. It's a benefit concert for the Columbus Urban League. It was actually my boyfriend's idea! Since there's a concert & he loves going to them, he wanted to go, so we got tickets. They include dinner. And it's black tie, so we get to get all dressed up! (I am more excited about that last part than he is.. I can't wait to see him in a tux). I'm actually wearing a dress I had to wear in a wedding last fall.. it's bright red, A-line, nothing fancy. I just love RED!!
I'll have to get it hemmed, but that's it. So, for those of you alums who miss the formal thing, I'd suggest looking into local benefits. There are a few of them here in Columbus right now.. I think it's the time of year for them or something. But it's a good reason to break out your old dresses that no one there has seen you wear & enjoy getting all gussied up.