Awhile ago, I answered an ad and took an online test for a position where I'd be sole sysadmin and support person for a camp in the mountains. Terms were $20 per hour and room and board, but I'd get snowed in reguarly. I aced the online test, and went up for my interview. On arrival, I was told to be subtle, as the person I was replacing was still working there, and didn't know he was leaving. Welcome!
After the interview with the owner (old lesson: Sole Proprietors are crazy) I met with various high level users, to discuss their problems. In each case, I suggested a solutions, some of which were implemented then and there.
Not a place I was eager to work, but I'd been out of work for a long time, and they were eager to have me. Fortunately, I took a position which payed a great deal more, wasn't an insane environment, and I never looked back. The camp did hold the position for me for quite some time, in case the other job didn't work out. Just a data point about the "working interview."