Spice up Goblinball matches by letting random pick up buffs appear at field randomly.
Lets say each 2 minutes a buff appears somewhere on the field and if anyone runs through it, the buff changes things around (for everyone).
Or just apply random buff each 2 minutes automatically.
Examples:
Speed buff: everyone starts running 50% faster for 30 seconds.
Size buff: everyone grows in size 50%, and their block circle grows 50% too, for 30 seconds.
Defense buff: goal space isn't limited to one goalkeeper anymore, everyone who enters it gets goalkeeper abilities, this buff lasts for 1 minute.
Multiball: a ball splits up into 3 extra balls (extra balls appear lined up on center starting positions), all balls are interactible and they last until one team scores the next goal, after which game resumes from center with 1 ball again.
(more fun buffs could be invented)
You could leave regular goblinball (5 matches per day) and add different queue for crazy goblinball (also 5 matches per day, separately counted).