In the aggregate, Children's Week is one of the most entertaining annual holidays. Dragging a small child with you around Azeroth's grand vistas and dangerous places is surprisingly fun ("I want to go to the Dark Portal." "Sure, why not?"), and it's a fairly immersive reminder that the planet's constant wars have almost certainly left a large population of orphans for each faction to rear. Also, getting a pet or the aptly-named Curmudgeon's Payoff is pretty cool too.
(You knew the "but" was coming.)
Unfortunately for all of you poor sods who still don't have School of Hard Knocks, that achievement still exists. I hated it so much that it was the sole remaining achievement between me and What A Long, Strange Trip It's Been for a year. With account-wide achievements, you no longer have to do it on multiple characters (and the whole system was worth it if for no other reason than that), but you'll still need it on one. Sorry, folks.
Anyway, Children's Week 2013 runs from April 29 to May 6, and, as always, the achievements and the meta For The Children are part of the year-long What A Long, Strange Trip It's Been.