The E4 Secret Santa announcement thread and Secret Santa result threads for 2017 are both still stickied in the General Boards tab if you are curious. The other years can be find pretty easily with the title search function as well.
I’ve participated two years thus far. For any new members, or members who never participated before: all the rules of 2017 can be find in this post right here, and this year will probably be pretty similar: www.elitefourum.com/t/e4-secret-santa-2017/18324/1
In general, you get a name assigned of someone who also entered, with a list of their favorite Pokémon and general collection interests. Then you’ll buy any gifts for that person. And the most important part: You create a drawing to send with it (this is mandatory, no matter how bad you are at drawing/painting. 
).
I personally really enjoyed the last two times, and will certainly enter again this and in upcoming years. And although I hadn’t drawn since I was a kid, I didn’t do too shabby if I say so myself:
[SPOILER: Click to show](javascript:void(0)
Click here to see the drawings
PS: It feels odd talking about Christmas when it’s 35 degrees outside… 
(Although I guess that’s normal for people from Oceania.)
Greetz,
Quuador