Well, that's just the thing, and that's why we haven't been using grounding as a punishment lately. But the transgression was serious, so there you are.
She'll be going to school, drivers ed, and work, but outside of that she's home. No phone, no computer. How perfectly fun for me. NOT!
Put her to work. I used to have mine do "obscure cleaning." Something I got around to once in a blue moon. "How come I've never seen YOU do it???" "Because I was saving it for when you got grounded."
;o]