I hope people don't do this but if you feel the need to block a member's content from your experience, you can do the following:

Click on the "gingerbread man" icon next to their name. This will trigger the mini-profile popup for the person, where you will see a new "Block Member" option. Click on that to block (or un-block).

You can also manage all of your blocked members on (menu up top) Manage > Your Block List.

the doomsday device! 

Tried that, it does not work as I would have expected.

What do you mean by "blocking member's content from your experience"? Does that include topics started by the blocked member?