I'm not suggesting that you do this, and I would never approve of fiddling with dangerous things that can have high liability issues, but...
As I'm sure you know, the wall sockets are on several different circuits. Its possible for half the wall sockets in your home to go out temporarily, and the other half to still be powered.
During a recent power outage, my co-workers informed me that several of them had CUT THE MAIN BREAKER FROM THE CITY TO THE HOUSE, and then started up a common "Home depot" generator and plugged a "double male" extension cord from the gen to a wall socket. Every circuit connected to that particular wall socket then had power. This gave them a refrigerator, microwave, and TV.
I was informed that if a running generator is still hooked up when the breaker is re-connected, damage to your home and generator will ensue (impossible to perfectly align the city/home-gen phases).
If a lineman is re-connecting what he believes is a "dead" line (isolated and tagged-out by the city), and you connect the main house switch when the gen still running, the lineman will be electrocuted.
This works, but it is no casual hacker tip.
"The boys throw stones in sport, but the frogs die in earnest" -Roman proverb