What's a good gift idea for a 4-year-old girl?

I’m going to the birthday party of my friends’ daughter. She’s going to be 4. It will be fun. All the usual birthday party things at a park. Fun for the kids, and fun for the adults.

What are some good gift ideas?

The girl is bright and inquisitive. I don’t spend a lot of time with her, so I don’t know her very well. She is also quiet and reserved. I gave her PlayDoh last year, and she liked it.