Using the code below, how can I use the DataContractJsonSerializer to convert the resultant list to JSON?

ETA: I have seen several extension methods to generically JSON-ize objects, but I'm not sure what type to use, as this is an anonymous type.

```
<Product> products = GetProductList();

var orderGroups =
 from p in products
 group p by p.Category into g
 select new { Category = g.Key, Products = g };

```

Thanks!