I like building stuff and I've run out of ideas for stuff to build given my constraints.
I would love to build a kit car, but they're kind of impractical and upwards of $50k.

I was recently going to buy a speaker kit (www.madisoundspeakerstore.com/2-way-speaker-kits/lxmini-linkwitz-lab-speaker-kit-pair/) but they're too hard to drive for my available amps.

Requirements:
1.- Smaller than square 1m.
2.- Complicated.
3.- no requirement to machine wood or metal parts, I don't have the tools.
4.- < $2k

I've built:
dozens of drones (quads, hex and octos).
Helicopters.
RC trucks, cars, buggies, crawlers, drifters...
Class A and A/B Amps tubes and ss. Neil Pass JLH...
Robot... crap one bcos they're expensive.
Lego, LOZ... many; even built the new Chiron in 7hrs which was boring.
Nixie tube clocks... 6 of them.
Various tesla coils, measuring instruments (LCR, oscilloscopes), function generators, electronic nick nacks.
3D Printers.
100's of mods... pretty much everything electrical is now voice activated, I am greeted by Google TTS when entering the house.