Elders at Lunar Festival

During the Lunar Festival, there will be 75 Elders spread around the world. Some are located in towns, some in instances, and some in the wild. Each gives you a  [Coin of Ancestry]. Note that each Elder may tell you the location up to 5 other Elders in nearby zones.
You can only receive one coin per Elder. The quests for receiving coins
are reset from year to year (previously, some characters were affected
by a bug that made seasonal quests unrepeatable in subsequent years,
but this issue has been corrected. i.e. The quests have been reset in
2008 and are all "re-doable". They were not reset in 2007. It is
expected that they will be reset for 2009).

Coins of Ancestry
can be turned in for several tailoring and engineering patterns, as
well as other items. Each coin you receive also generates 75 faction
with either the Horde or Alliance for a total of 5625 for most races and 6187 for humans if all 75  [coins] are gathered. Furthermore, each Elder you visit will send you a  [Lucky Red Envelope] via in-game mail which contains  [Lucky Rocket Cluster] or an  [Elder's Moonstone]. Using the  [Lucky Rocket Cluster] gives you the Lunar Fortune buff (+250 health).

Through the Achievements system, players are rewarded for participating in the Lunar Festival. 160
achievement points are available through 14 achievements. Upon
completing all of the Lunar Festival achievements, you will complete
the world event achievement  To Honor One's Elders which gives the <Elder> title.

Note that, up until now, no one has provided a reliable guide on how to get to Frosthold without a flying mount, and since it is a long way up, you might not be able to do  Elders of Northrend before lvl 77 without help from a warlock. Also note that Elder Ohanzee can only be reached in Heroic Gundrak, rendering anyone sub-78 unable to complete  Elders of the Dungeons. So you'll have to be level 78 or higher to complete the meta achievement  To Honor One's Elders and gain the <Elder> title.