Workshop Boosts are a relatively new feature in CastleVille Legends, that began being rolled out in December 2014. They are currently in limited circulation, but below is all I know about them from having earned and used one.
Caveat: My boost was a x2 (times two) for the Woodshop, that I earned by completing the Giovanni's Workshop Boosts quest. I know that they will eventually be available for other Workshops, but I don't know if they'll be available for ALL workshops. Likewise, I don't know if they will eventually come in flavors other than x2 (such as x3, etc.), but it's possible.
Below are screenshots from when I used my Woodshop Boost. This first one is how it looked after I clicked the big green "Select a Boost" question mark:
Then, after I chose the item and started crafting, I could clearly see when I clicked on the Woodshop that the item was being crafted "x2":
Here is the rest of what we know so far:
- Boosts allow your workshops to produce twice as much of something in the same amount of time as it would normally take to make one. So for instance you get two Wooden Shields instead of one.
- You only need enough input to craft one item; the output is then magically doubled. In other words, if you were crafting a Wooden Shield, you would only need 10 Logs, not 20. This makes it especially handy for use on items which have very rare ingredients!
- Once you select a boost, you have only five minutes to get crafting! So make sure that you have all of the materials needed for what you want to craft, on hand and ready to roll.
- Giovanni's Contraption, and the process of refueling it, has something to do with Workshop Boosts, though we don't yet know what. My suspicion is that it is how you will normally get boosts, but obviously it isn't the only way, since some are being given out as prizes to the top-ranked folks in the Winter 2014-2015 Yule Seasonal Event.