Please consider putting these events on Steam as a News item.
This would increase visibility and potentially attract new players.
This is the page I refer to, and it is my default view upon opening Steam:
http://store.steampowered.com/news
Edited to add that this page announces:
Sales (lots of those)
Updates to TF2
Updates to DOTA2
New DLC (like the new mech body that just got released)
Edited by SGRock, 18 April 2015 - 10:10 AM.