I've been burned by a few bugs recently due to swallowed exceptions. In case you don't know, empty catch blocks will hurt you. Really, they will.
I wanted a way to locate all of the empty blocks in our code base, I was playing around with NDepend and the amazing Code Query Language, but it's not able to do something like this yet. (Patrick said that it will in the next version!)
Then I realized that I was missing the simple solution. 
Ctrl+F and a regular expression!
Here is the regex you'll need to find empty catch blocks in your solution:
catch:Wh*\{:Wh*\}
":Wh" designates whitespace
* means zero or more
You have to escape the {} as they are special characters.
Update: Note Dan's comments below. Here's an updated regex to cast a wider net:
catch(\(.*Exception.*\))*:Wh*\{:Wh*\}