If you are getting yourself ready for tonight's 12:01 a.m. PT launch of StarCraft 2: Heart of the Swarm, just a reminder: Make sure you have StarCraft 2: Wings of Liberty still installed on your PC. This will not be a standalone expansion.
Granted, if you continue to play multiplayer, you will still have it on your system, all properly patched and ready for the zerg infestation. But those of us who aren't in it for the multiplayer (including me) will need to start reinstalling. If you don't have your game disks any more, you can still download it from your Battle.net account. Of course, if you never played Wings of Liberty, Blizzard has it on sale.
Also, Blizzard is running livestreams of some of the various launch events around the world, so if you want to see others having fun while you are sitting at home waiting to click "play," then tune in.