Push all the chairs together, throw some blankets on top and make a fort. You can read books and have lunch under there.
Throw all the sofa pillows and cushions on the floor and she can jump around on them.
Place a bunch of plastic cups spread out on the floor and see if she can walk around them w/o knocking them over.
Roll up a bunch of socks and see if she can toss them into the cups w/o knocking them over.
Throw the rolled up socks at each other and have a "snowball" fight. Or use cottonballs.
Give her some sugar or flour w/a few bowls and a mixing spoon and she can pretend she is cooking. Use rice, popcorn kernels or dried beans if you don't want a mess. I used to put rice, kernels and beans in my crockpot on the floor (b/c it was heavy and he couldn't move it) &my kid would scoop out some and pour into a few bowls on the floor. Then he would dump them back into the pot and start all over again.
Turn on Foodnetwork TV w/her play dishes and food and she can copy the chefs. If you can push her play kitchen by the TV, even better.
Turn off all the lights, get some flashlights and have a lightshow in the dark. Mirrors make it fun too.
Give her a stack of post it notes and let her stick them whereever she wants to.
Give her a roll of toilet paper (make it clear she could only do this one time) and let her play w/that. Teach her to roll up her dolls like mummies.
Plug your video camera to your TV, turn on some music, and she can watch herself sing and dance.
Give her some make up and a mirror. She can give herself a makeover...you too!
Fill the sink up w/some water, give her a few plastic dishes and a scrub brush/pad and let her pretend to ''wash" the dishes.
Go to a home improvement store. The aisles are wide and chances are it will not be crowded at all. Plus it will be heated/air conditioned. She can run up and down the aisles and look at everything. My kid loved to open and close all the doors on the ovens, fridges, washers/dryers, play w/the vacuums, play in the model kitchens and bathrooms, turn all the knobs, look at all the wood planks, play in the showers like he was in a spaceship, sit on all the tractors, collect paint samples...we used to spend hours there on rainy days.
GL and HTH