Vindictus has done just that in the European region. To celebrate, EU players are being given wings. Some of them, anyway. The rest are just going to have to purchase them.
Here's how it works. When players are logged in at 6:00 p.m. GMT (1:00 p.m. EDT) between today and September 27th, they have a chance to receive the second anniversary gift box which contains a free set of Phoenix Wings. Players not logged in on at that time can purchase the wings directly for 35,000 NX during the limited sales windows: 4:00 p.m to 6:00 p.m. GMT (11:00 a.m. to 1:00 p.m. EDT), September 28th until October 3rd.
Players who are uninterested in chasing wings can also take part in the new Siege Mode PvP matches by speaking to the Battlemaster in Rocheste. So everyone gets something for the second year.