Exclude category from Recent Posts in sidebar

I do not want the latest obituary posts showing up in the Recent Posts sidebar widget on the left.
http://larchmontgazette.com/wp27/

I want to be able to exclude obituaries and maybe some other categories, in the future, from the sidebar widget. I tried the Advanced Category Excluder plugin, but it didn't do a thing for me. I don't see any other likely plugins when I search the Wordpress plugin directory.

Help!