set up obstacle courses going under, over, around, through various things
make a tent out of a sheet and table
get the cars out of the garage and let her do ride on toys in there
put pillows on the ground by the bed and let her jump onto the pillows from the bed
put pillows in a row and have her jump from pillow to pillow
buy Baby Songs ABCs and 123s DVD and do those activities with her
buy yoga for kids DVDs and do those with her
there are some wii games that are for that age that are active, check reviews on amazon to see which are really good and which aren't...
buy a small climber or slide and put some pillows under it and let her play on that, if you already own one and use it outside clean it up and bring it inside
go for a walk with flashlights