Op, I applaud the creativity but a rave shower sounds like it would induce pediatric epilepsy. (Did you belong to a sorority by any chance?)

I used to do random upside down dinners where my kids got to eat ice cream before dinner. My kids are now in their 20’s and they still talk about it.

Sigh. I long for the days of little kids. Teenagers are so much harder.

We add water into zip bag then add food coloring and/or small toys then freeze it, then DCs enjoy playing the colored ice on drive way, they think it’s pretty and fun to play with.

I saw an idea on the busy toddler website where you put different colors of food coloring in the wells of a muffin tin, cover in baking soda, and give the kids a bottle of watered-down vinegar to squirt in there and watch it bubble up and make colors. Looks fun.

Or you could just give them empty amazon boxes, a roll of tape, cardboard tubes, and some bubble wrap and ask them to build something. Entertains them for hours with less effort and cleanup on my part.

Butterfly Pea Flowers! I steep them in boiling water to make iced tea. Then I let my daughter pour lemon juice into it. It goes from a dark blue to a pinkish purple. I call it a magical unicorn drink. She's so enamored by it!

OP, have you ever read the busy book for preschoolers? It has tons of ideas like this!

https://www.amazon.com/Preschoolers-Busy-Book-Creative-Activities/dp/0671316338/ref=asc_df_0671316338/?tag=hyprod-20&linkCode=df0&hvadid=312057360383&hvpos=&hvnetw=g&hvrand=14357402283399306493&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9060365&hvtargid=pla-436629020581&psc=1

Naked sticker dance party. The kids love it.

I get a random treat for them at the grocery store. When I get home, they both help me unload the bags until they find it

At those ages, there are so many ways to make things fun. Anything that adds elements of imagination can transform the normal into something magical, just like playing "restaurant."

Other ideas:

Play school.
Periodic dance parties always lifts spirits.
Do some sort of exercise class together, where you all work out (for them it will be jumping up and down, but).
Camping, either backyard or indoors.
Fort building with blankets and pillows and chairs
Makeover Day (let them put makeup on you)
Scavenger hunt

The other day I got my 4 year olds to spend a solid chunk of time helping me to clean the basement - I'd hand them stuff that needed to go elsewhere in the house, tell them where to go, they would run to put it there, and then come back for more. They were super into it (like it was a game) and I actually got something checked off of my list (with no planning, effort, props - other than having a pile of stuff that needed to be sorted out).

For that age I would invest in a really good bubble machine (the cheap ones break easily). Those kids go bananas for bubbles. Put on some good music and have a bubble dance party.

The times when I have tried to make the day more exciting, it more often than not backfires and the kids didn't love it and I was grumpy about the extra effort.

The things that totally make their day are usually things they come up with when they are bored out of their minds.

Yesterday we went out for ice cream - didn't have to enter the store and the entire thing took 20 minutes, but my kid was thrilled.

Just looking for ways to make the day to day a bit more fun on occassion - with very little effort or $ involved.

Two I've done that are hits (for context i have a 3 and 2 year old)

- Rave showers - bathroom lights off, glowsticks from target $1 section, shower paint (yogurt + food coloring if a kid might eat it, shaving cream and food coloring if not), music. Easily kills an hour total.

- Pizza restaurant Fridays - for some reason calling our dinner at home "a restaurant" makes it way more exciting for them. chef hat, cheap table cloth, kitztch italian music, dimmed lights, fake italian accents to talk about the pizza