We had a thread on this a long while ago, but I had an excellent one last night which would appeal to the... ahem..'older' gamers here.
In GTA:Vice City, I'm driving along the seafront in my silver Cheetah, its dusk and then on the radio comes 'Crockett's Theme' by Jan Hammer... OMG! I'm transported back to 1987 when pastel coloured sports jacket over white t-shirst was the coolest thing out and you watched Miami Vice religiously to be able to yack all about it at school the next day.
It was all I could do to not get into the loft and dig out the suitcase full of clothes in different shades of lilac and yellow...
What a game....!