If you want things to do that are just like every day stuff, not a vacation you could go to the zoo or look for kid friendly museums like natural history or childrens museum. A lot of museums and similar places will have a free/cheap entry day once a week or month, check their websites. The library is always good [and free], look for a branch that has story hour or similar program.
Also try the YMCA or city parks and recreation department. They frequently have classes or activities for younger kids like tumbling, art classes, swimming lessons, etc. Its usually pretty cheap though it does vary by town I guess. If they have good facilities for younger kids [a lot are more for older kids/adults?] then see how much it costs to join or if they have any financial assistance/reduced membership rates.
_______________
[url=http://eagleoutside.com/]Outdoor recreation Colorado[/url]