Thanks for your feedback @Enric_Moreno!
Yeah actually I started compiling more things and will probably prepare another post or update this one with more ideas sometime within the next months.
One thing I started testing is running short funny and even off-topic votes randomly during the week such as “Salty or Sweet Popcorn” (this one I posted on “National Caramel Popcorn Day”) and then the team had a fun convo about it joking why people would prefer sweet popcorn in cinemas for example. Was a nice short distraction during a tough working day.
I started doing such short votes randomly on various days and the team has fun with it.
Now to even improve on how such votes display (instead of listing the options in subtasks for example and get the team to upvote) I cannot wait for this feature to launch 
Now in terms of the Monday & Friday motivation sure I will compile some I used and share within the next days.