This happens to me 1 or 2 times a day, I'm playing a game and suddenly 1 or more than 1 keys get stuck. And by stuck I mean not physically stuck but its sending that key over and over again like this vvvvvvvvvvvvvvv :P Then after a while these keys stop working and more and more keys get stuck. I can fix this by un plugging the keyboard from my computer but I would still like to find a real fix to this and I got the drivers for my keyboard...
Maybe try re-installing the drivers and also what keyboard are you using?