It might be too much of a squeeze, and there might be nothing like this around you, but...
This year we were running low on funds for a nice big vacation, so we decided to vacation at home. Being the busy body that I am, I had to do at least one fun thing and that was to take the whole family (me, DH and 7 year old DD) to the Great Wolf Lodge (about 2 hours down the road). We're just doing it one night, but it's a pretty good deal -
For $230 me, DH and our 7 year old DD get free passes to their indoor waterpark during our stay. We can arrive early and use the waterpark all day, and leave late - still getting to use the waterpark. Great Wolf Lodge had a ton of other stuff to do there as well. I'm not sure who's more excited, me or (when I actually tell) our 7 year old.
The library idea was good, and the YMCA... liked that one too. I'm also using some of the vacation time to do an early Spring cleaning (luckily the weatherman is cooperating and saying our temps will sneak up in to the high 60's mid week).
Have fun... good luck!