Ideas for my sister's 50th birthday?

My sister is turning 50 in two weeks, and she told me that she doesn’t want a big deal ‘to-do’. It would only be immediate family and it is difficult for my sister to travel (she lives an hour from us), so, it would have to be at her place. I was thinking of having something in her backyard. She’d feel more comfortable at home, as opposed to going out for dinner.

Any ideas? Something special.

Thanks.