Crushing, depressing boredom. Suggestions?

Three days of holding down the fort, just myself and the dog, have convinced me that I should cultivate some more social activities. Most of my friends are still in school, or work, or both (making it hard to plan activities in the short-term), so I think that I might need to make more friends.
I work, but I get two days a week off and they, and my hours, move around too much for any sort of regular activity – they plot the schedule out to three weeks, and that’s it.

The depression isn’t anything major – just a side-effect of the boredom- but it is annoying.

Suggestions?