I don't know much about technology in London, but history buffs should not miss the Tower of London (http://www.hrp.org.uk/toweroflondon/) and Churchill's War Rooms (http://cwr.iwm.org.uk/). I would also recommend spending a few hours on a double-decker sight-seeing bus when you first arrive, to get an overview of the city (http://www.theoriginaltour.com/).
Summer about 10 years ago
Well you won't be disappointed on the history side - London has heaps of history. The double decker is a great way to get your bearings - would do this first to mark out the spots. If your going to be dragging your poor boys into the "shops" like harrods etc. Pick your times I always was found first thing in the morning was a good time as they do get very busy with lots of tourists during the summer time.
If the weather is nice: Grab some basic picnic stuff and head to a lovely green London park and enjoy the scenery. Find a lovely pub on the Thames for spot a lunch also enjoyable experience.. Some nice spots around Chiswick area.
The London eye is a great experience the natural history museum is also worth checking out..
All the best
James of littlenomads.com about 10 years ago