I've been out of school for two years now. I'd say I'm still very active.
I belong to an alumni chapter, where I am the secretary.
I am also the national editor for my GLO, which makes me a part of our "National Council" (sort of like a Board of Directors or Natioanl Executive Board).
As for being directly active with my undergrad chapter: I'm not as active as I'd like to be. Right after I graduated they asked me to be their new alumna advisor. I turned it down because I still had several friends that were active, and knew I could be placed in some akward positions. I try to go to as many events as I can since I'm in the same city. Since I work nights, this can be hard sometimes. I go to chapter events as well as individuals' events (like senior recitals). I've been to initiation cereomonies and recitals and things. It's amazing that in 2 years I hardly know anyone.
I do maintain their chapter web site (click on "Phi Beta" in the signature) so I am in constant email contact with a few members to keep accurate, up to date info on it. That's one way I give back to the chapter.
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SilverTurtle
Phi Beta Fraternity: National Professional Association for the Creative & Performing Arts