People use the phrase "There's so much to do" in two situations:

1. When talking about a place that has a lot of fun activities available.

   I love Paris. There's so much to do there.

2. When talking about the amount of work that they have to do.

   Wow, there's so much to do today! I don't know where to start.

You can use several different words in the phrase to describe how much there is to do. For example, "there's nothing to do" is a complaint that kids sometimes make when they're bored.

This is boring! There's nothing to do.