Plug in socket adapter? http://electrical.hardwarestore.com/12-34-outlet-adapters/plug-in-socket-adapter-102955.aspx
what your probably thinking is a mogul adapter. regular houshold bulbs use medium sockets. However larger watt flourescent bulbs often use a mogul socket. You can buy one of these adapters for about five bucks, but be careful. Make sure your flourescent bulb has a built in ballast or the voltage will probably blow your bulb.