Hi L.,
I totally understand the wanting to be with and wanting to be without. My son is now in full-day Kindergarten and I hate that he is away that many hours already - but try to enjoy the time to myself when I can.
Anyhow, what about taking a class at the community college? I am not familiar with the colleges in Tucson but Maricopa Community Colleges here have a WIDE range of classes. Something I always have wanted to do but haven't is take a sewing or knitting class (prob. limited on meeting potential dates in one of those! haha) or a martial arts class, or join a like minded group (i.e. vegetarian group that shares dishes/recipes).
What about a book club, film club, music club? Craig's List is a great place to find events..or even start one on here? A friend of mine is in a running club. They meet on Saturdays and run (preparing for a 1/2 marathon).
I would love to start an Indie film or foreign film club or a philosophy/book club. My dad says it is elitist but I think it would be fun! I so miss the adult intellectual interaction I had when I returned *gasp* in my 30's to university.
Or even getting some sort of degree or certificate from UofA?
Perhaps a better question is what is it you enjoy doing - then look for ways in which you can find others to interact with while doing what you enjoy. =)