|Interested in plugs and sockets and/or historical electrotechnical material ? Then you may like having a look at:
Electrokinetica, bringing together a comprehensive collection of electrical and electronic artefacts in a working museum encompassing the first 150 years of electrical technology. See http://www.electrokinetica.org/
Museum of Old Electrical Items (UK only): sockets, plugs, conectors, adaptors and many more; images and informative texts.
The Bakelite Museum in Williton, Somerset, UK is home to the largest collection of vintage plastics in Britain.
Find details on http://www.bakelitemuseum.co.uk/
Note that there are more Bakelite collections, in various countries, that can be visited. Your browser will help you to find them.
Wikipedia page about mains power connections devices used in domestic and light commercial environments.
Electrical Contractor Network (ECN). Discussion Forums for Electricians, Inspectors and Related Professionals. Here you will find many pages of (US) electrical nostalgia. Browse at http://www.electrical-contractor.net/forums/ubbthreads.php/forums/17/1/Electrical_Nostalgia
UK Vintage Radio Repair and Restoration. Discussion forum on vintage household electrical or electromechanical items.
See http://www.vintage-radio.net/forum/showthread.php?t=71262 (several pages!)
No doubts, there is more.