#9 - Sam caught watching porn "“ "Children Shouldn't Play with Dead Things."
Keep in mind, this is early season two. After all, Sam spent most of the time at this point hanging around in motel rooms with his brother and brooding over his dead girlfriend. Of course we thought he lived like a monk! Imagine our shock to learn he's a horndog after all. What makes this bit better? Dean's single worded reaction. "Awkward."
Actually, this episode features not one but two Sam Winchester eye popping moments. The other, when Sam pulls his gun at the cemetary, is only a "brief" encounter, but it certainly gets mention every now and then.