Bliizard has officially acknowledged that a StarCraft 2 bug might fry graphics cards.
The official Battle.Net support page explains that "screens that are light on detail may make your system overheat if cooling is overall insufficient. This is because the game has nothing to do so it is primarily just working on drawing the screen very quickly."
The bug is caused by the fact that StarCraft 2 has no frame rate limit. Fortunately, such a limit can be imposed fairly easy by adding the following lines to Documents\StarCraft II\variables.txt file: