Family Fun magazine from Disney usually has a number of good ideas and they have a website you can use http://familyfun.go.com/
Try recycling things. We used a lot of toilet paper tubes and paper towel tubes to make different things. I'll cover them with different construction or wrapping papers and make puppets by glueing different pictures to them (happy meal's have great things to cut off the boxes and they're sturdy). I don't know if you have a boy or a girl but we made "man" wands for the boys so they could have magic wands to use like Princess presto on Super Why when she writes in the air.
Crayola color wonder is great because there's no mess but they aren't that expensive.
Being down south, bubbles are huge. And Target had great sandbox cars for $1 (clearanced at less) that we have all over the house and porch that they love to play with.
Sandboxes are also good but you'll want one that's covered. They love to drive their cars over ramps and make sand castles.
Make forts with pillows or tents with a sheet inside. Indoor picnics are fun too.
And my boys love to bake and cook. We make a ton of cookies. Just make sure you have volunteers to take them off your hands because it went to my waist quickly.
Have fun!