The 20th Birthday Celebration. Cartoon Network devoting the entire month of October 2012 to celebrate their heritage past and present. All the fans on forums like Toonzone and 4chan admit that while the network has made some mistakes (the live-action shows, someanimatedduds, all of which have been canceled and barred from rerunning), they praise the network and thank it for 20 wonderful years of memories.
After the death of Chuck Jones in 2002, what did the network do? They aired four straight hours of Jones-directed shorts the following weekend on The Looney Tunes Show (not the sitcom, the installment show featuring nothing but Looney Tunes and Merrie Melodies cartoon shorts).
The In Memoriam segment from the Fancy Anvil Awards show, which presented tributes to William Hanna, Chuck Jones and Maurice Noble.
Their tribute to Joe Barbera when he passed away in 2006.