**UPDATE**
Epic now gives you 29/30 events on all characters within the game. Play one event as defined below (play a public match of any game type) and you will get the achievement. I have tested this with a new account and was able to get the achievement.
**Archived Information**
In order to earn the Socialite Achievement you are required to play in 30 seperate & unique Gears of War 3 Events. The events so far have followed a pattern of every week and cycle the same 35 (or so) events. If you have already won the ribbon or played that event you will not get another ribbon or get credit for that event. Some of the events are shown on the Calendar & Events on the main menu, but Epic does not seem to update this page on a regular basis. During most events, you only need to play a quick, ranked or private match (Beast, Horde or Multiplayer) resulting in receiving a ribbon for that event. It is no longer required to play a specific playlist.
Important Notes:
The events cycle, don't know right now if it is random.
If you received the ribbon for an event, you cannot get it again.
Events 1-35 is the original list I created of cycling events (Main Events).
Listed are the past events, I will no longer keep this updated do to the lack of structure and order that Epic is providing.
Event Title - Start to End [Props/First person to let me know]
Rotating Events:
35) Shot Through The Heart - May 11th to May 14th [xZer0ex via post]
34) KOTGnasher - May 5th to May 8th [Wannabe Actuary via PM]
33) My Baby Shot me Down! - Apr 27th to Apr 30th [xZer0ex via post]
32) Creapy Crawly - Apr 20th to Apr 24th [Naughty Died via PM]
31) Struck by Lightning - Apr 13th to Apr 16th [LGS I Hitman & TE4RIN IT UP via post]
30) Easter Bunny Hunter - Apr 6th to Apr 9th [Icy iNs via post]
29) Raven Down Survivor - Mar 30th to Apr 2nd [merkins via post]
28) Forces of Nature - Mar 27 to Mar 29 [LGS | Hitman via post]
27) Torque Tagged - Mar 23rd to Mar 26th [LGS I Hitman via post]
26) Almost Time for DLC - Mar 15th to ??? ??? [LGS I Hitman & Piemanns Bakery via post]
25) Gnashers 4 Life - Mar 6th to Mar 10th [ComesBrothers via PM]
24) March on Gears - Mar 3rd to Mar 6th [Gumbeaux Jr. via PM]
23) Can You Dig It - Feb 24th to Feb 27th [Cobryza via PM]
22) Boom Snipes - Feb 17th to Feb 20th [xDevilz 1 via PM]
21) Cupid's Wingman - Feb 10th to Feb 15th [Un4given Raider via PM]
20) The Grayson Cup - Feb 3rd to Feb 6th [semi kid via PM]
19) Get Gnashy - Jan 27th to Jan 30th [o Progressive o via post]
18) Winning Weekend - Jan 20th to Jan 23rd [xDevilz 1 via PM]
17) Horde Dance-a-Thon - Jan 13th to Jan 16th [mr matty uk via Post]
16) Stranded KOTH - Jan 6th to Jan 8th [Sedgendary via Post]
15) Triple Team - Dec 29th to 31st [SixtyFootMonkey via Post]
14) The Twelve Days of Gearsmas (Part III) - Dec 21st to Dec 25th
13) The Twelve Days of Gearsmas (Part II) - Dec 17th to Dec 20th
12) The Twelve Days of Gearsmas (Part I) - Dec 13th to Dec 16th
11) Brothers to the End - Dec 9th to Dec 12th
10) This Is My Rifle - Dec 2nd to Dec 5th
09) Thanksgibbing - Nov 24th to Nov 28th
08) Blades and Nades - Nov 18th to Nov 20th
07) One shot, One kill - Nov 11th to Nov 13th
06) Can you dig it? - Nov 4th to Nov 7th
05) Happy Halloween & Boom Snipes - Oct 28th to Oct 31st
04) Hardcore Weekend - Oct 21st to Oct 24th
03) Torque Bow Tag - Oct 14th - Oct 17th
02) Big Head Mode Weekend - Oct 7th - Oct 10th
01) Golden Wings week - Sep 20th - Sep 26th
Events are also listed here, sometimes:
http://epicgames.com/community/category/gears-of-war/Thank you to the community for your continual support in this guide.