I think I have to agree with Boing Boingers on this one. Never thought that I would see an ad like this. Go to the Boing Boing site for the direct link to the jpg file.
Boing Boing: Anti-MMORPG ads from D&D
"This anti-MMORPG ad from Dungeons and Dragons is STONE BRILLIANT. It reads 'If you're going to sit in your basement pretending to be an elf, you should at least have some friends over to help. Dungeons and Dragons: Get together. Roll some Dice. Have Fun.' Way to play to your core strength."