There are a ton of non-official meets going on. Do a forum search for any of these events, there is at least 1 thread on each event
http://www.disboards.com/showthread.php?p=34114769#post34114769
There are other meet ups and events that are being organized by DIS'ers, but not official DIS Events. Some of these include:
DVC Merry Mixer Meet on Thursday 12/10 @ 3pm-5pm. Cost: Membership in or Guest of a DVC owner.
Social viewing of Osborne Lights at Disney's Hollywood Studios on Thurday 12/10 @ 6pm. Cost: Park admission.
7th Annual Jellyroll Meet at Jellyrolls on the Boardwalk on Thursday 12/10 @ 8pm. Cost: $10 cover, plus your food and drink.
Yeehaw Bob @ Port Orleans Riverside on Thursday, 12/10 @ 8:30pm. Cost: Free admission. Buy your own food and drink.
Lunch @ Fulton's at Downtown Disney, Friday, 12/11 @ 2pm. Cost: Your food, drink and tip.
Pre-DATW "Make sure they don't run out of Slushies!!!" Meet in France, Friday, 12/11 @ 4:45ish. Cost: Park Admission and slushie, if you choose.
Kathy's Peeps ride "Journey Into Imagination" on Friday, 12/11, around 5pm. Cost: Park admission.
Drink Around the World, Version DAP '09. Starting in Canada, World Showcase, Epcot @ 5:30. Cost: Park admission. Buy your own food and drink.
Give Kids the World voluntourist experience. Donate a couple hours at Give Kids the World on Saturday 12/12 @ 8am. Cost: Transportation to/from GKTW~see thread about this, people are looking to share a taxi or rental car.
Utilitarian viewing of the Osborne Lights at Disney's Hollywood Studios on Saturday 12/12 @ 7:30pm. Cost: Park admission.
Tonga Toast Breakfast at Kona Café/Captain Cook's at the Polynesian on Sunday 12/13 @ 9am. Cost: Price of food and drink.
Brunch at House of Blues on Sunday 12/13 @ 10:30am (tentative). Cost: Price of brunch + tax & tip.
Dole Whip for Bawb at Captain Cook's at the Polynesian on Sunday 12/13 @ 4pm (following the podcast taping). Cost: Price of Dole Whip.
Mickey's Very Merry Christmas Party on Sunday 12/13 (entry begins @ 4pm). Cost: Price of
MVMCP ticket.