how to remove from gnome menu

Anyone know how to pull entire categories out of the gnome menu? I've heard there's an application called smeg that does this, but when I (in ubuntu) apt-get install smeg I get nada (likewise synaptic). Really, for now, I just want to get rid of games across the board. My employees don't need games access (at least not at their work terminals, they can do whatever they like on breaks at the community system).

I've obviously never had a reason to do this sort of thing before, because I don't care if I have access to games here or at home, but on a large scale it's problematic.