What to do with kids for free.?

Ok so we have no money to go out and do anything. we currently have cars in the shop so we can't go anywhere. i am a stay at home mom of two young boys under school age. so their home all the time. we go to the park all the time, we have done everything out side , treasure hunts, picnics played sports , went on nature walks build tents. we have also done everything inside. I have no more ideas. I really want their father to do something with them because he is home all weekend but all he does is play black ops. and gets made or gives me excuses when i ask him to do something with them. I have no clue what to do with them, any ideas. I really wish either their biological father or any of their biological family would do something with them . I am just a step-mom and i do it all.