Blizzard Created-Mods
 
 
Like I said countless times, Starcraft II has a modding community that has the potential to produce either great maps or bad ones. The announcement of custom maps' marketplace sounds like a bad idea and maybe a way that the community will start ripping off, making their own map expensive so suckers could buy them and find out that it's complete garbage. We'll see how this feature is implemented in the future and how Blizzard will asset with this problem because Xbox Live also has a number of horrible Indie Games that costs the amount that they don't deserve. 
 
Now Blizzard often create their own maps/mods to download from their site, from Warcraft (III/Frozen Throne) to Starcraft ranging from skirmish maps to custom-created maps like DOTA to Tower Defense. Recently they started a beta-process with three custom maps that they created; Aiur Chef, Starjeweled and Left 2 Die and like any custom-created maps by Blizzard, it's not half-assed and actually fun. Here's the three maps located on Battle.net. 
 
 
  

  
 
The first map is Aiur Chef, get it? because Iron sounds like Aiur so it's a hilarious pun. Like Iron Chef, you're a chef competing against other chefs (total 8 players)  for the title of Aiur Chef - as you rush throughout the map, acquiring ingredients based on the theme ingredient and rushing back to the centre to get points. The harder the ingredients acquired, the more points you score and the most points won under pressure from the time that you must dash for the ingredients. There isn't much action, though acquiring ingredients often you have to kill specific creatures from Zerg Roaches for meat to picking up veggies, it's pretty much you trying to find the best ingredient for getting a meal with higher points or finding the easiest ingredient from the top-left corner of the screen and repeatedly doing that.  Also inventory space is limited so you can't hog up all the ingredients and have to do each dish one by one. It's like the real show with a Starcraft-twist. Overall it's alright, sometimes it's boring but trying to get the most points is kinda fun. This is my least favourite map.  
 
  

  
 
The second map is Starjeweled, a Bejeweled clone which you could play Bejeweled while playing WoW. Like Bejeweled, it's a match three game but instead getting the getting jewel combinations successfully, matching three or more gems which charges you're energy meter, you also have to use your purchase stronger units from your energy meter to destroy your opponent. It's like Bejeweled and Defend your Castle combined with a vertical map from top to bottom and base defenses. It utilizes the Starcraft II strategy of pitting a stronger unit against the AI/Player, like purchasing a Colossus to defeat Hydralisks to Zealots against Roaches. You also can perform abilities and spells like psi storm over your enemy forces or heal your own. You have to be efficient with how you handle your army, choosing the right unit against your opponent, strengths and weakness and using quick thinking and conversing your energy meter through five dreadful rounds, taking out your opponent's base out of the most rounds and you win! I love this map, the idea of Bejeweled and Defend your Castle mixed up together is pretty neat and fun, it's quite stressful to play it online seeing that people know what unit to build but I'm having a blast playing that game.
  
   

  
 
I haven't yet played Left 2 Die due to not seeing it online on battle.net (not the site, online multiplayer) but I heard it's one of the Starcraft II campaign, Outbreak where you have to survive a horde of infested terrans and keep them away from your base. Like the campaign, it shifts through day and night phases and through day time, you and your allies have the opportunity to destroy infested settlements that spawn infested terrans or resupply and build more units to reinforcing your defenses for the upcoming horde in night phases. There are also special zerg units that produces biomass after they die which you could use it to upgrade units and get better ones to support your army. And there's a challenge mode that there isn't a day cycle and only night, as well as each round being extremely difficult.  And also Left 4 Dead.
 
All in all, these beta maps are what good things to come for the community to make awesome mods and maps like someone already made a Metal Slug side-scrolling shooter and a RPG map with timed battles. Hopefully this marketplace that Blizzard is implementing in Starcraft II could be great!