When I got Blockland, the first server I ever hosted was a Shop Wars minigame.
Basically, how it worked was you would make your little store selling anything available, and as you sell more things you can make your shop bigger and have more locations and items.
The most popular shop with the most money (and working events to buy and sell) will prevail!
NOTE: VCE and Buy and Sell events are not included: the addons I use now are as affective if not more.
This is not an actual minigame, it doesn't need one to work.
should I host this again