At the craft store I bought my daughter sculpting clay that air dries. Its fun like play dough, but then you can paint it latter. In the craft department she also has an art box of colored paper, toddler scissors (keep those hidden except when doing crafts), stickers, stencils. She loves her arts and crafts.
She has a CD player and kids music CD's and that was a bigger hit than I could have ever imagined. She listens to music and jumps on her bed 2 hours a day!!!!
On special occasions we make something in the kitchen that will be fun for her. Keep is super simple, packaged brownies or cake so she can hold the mixer. She loves learning to cook in the kitchen. Next we are going to make bread, but thats going to be messy!!!!!!!!!!!
Fort making is huge (couch cusions and blankest, but the other day we set up a 4 man tent! That stayed up for a week and provided lots of fun)
Mine adores tea parties, but I'm sure there is a boy equilent (like going out in the garage to hammer some nails into a board)
special outings like indoor park, outdoor park, play date with other kids and she absolutely loves loves loves to go out to lunch, even if its taco bell.
My nephew love to build things with his grandpa. Maybe get something that requires building at the craft store.