Curious, I clicked the event and decided that I'll be attending too!
Here's the details, taken from the official Facebook event page:
"We've got days to wear towels, days to talk like pirates, but (according to a web search) this is the first planned Hug A Gamer day. So give your nearest geek a cuddle! They probably need it after all those pixels, but watch out for the Counter Strike reflexes. The date of this event is November 29th (the day Pong was released). Let us celebrate. Join in the hugs.(And invite as many people as you can so this can grow)."
Sounds like a pretty neat concept!
At the time I'm typing this post, 167,881 people are "attending" with thousands "maybe attending" or "waiting for response."
Whether you join the event/group on Facebook or not, do a gamer a favor and on Monday give them a hug!