Back in the day I was never an Amiga guy but I am now enjoying finding out more about this system. I would of had so much fun programming this system, putting myself back then with the spec it would have seemed like all is possible.
That said, I have always loved how the 8bit and 16bit software developers hacked the hardware to make it do more than it was supposed to. From the C64 playing samples and sprites in borders to the ST doing full overscan, breaking the hardware to do more using software is fun - the ST being the pinnacle of this (not saying it was better in any way just you could have a lot of fun messing with it big time).
I know that on the Amiga (let's say 500) you could do things like have serial ports run at higher speeds using software but was there any hack that stands out? I feel that most that you would want to do was already there in hardware but I would be happy to hear about pushing these normals to extreme and especially if software pushed them "out of spec".
For example I know HAM could produce 4096 colours on screen but it was limited in that adjacent pixels had to be related in colour, did anyone do a true 4096 screen (I could be wrong here)? Did anyone us Blitter to make synth music, I don't know. Just any cool leverage of hardware in software is of interest to me.
If others like this theme, there is a CGA demo in full colour (look for area 5150 demo) and the Commodore PET "No Pets Allowed" (this machine could not do graphics, incredible), there is a ZX Spectrum game with no colour clash, there is a demo running on a C64 floppy drive (look for 1541 demo).
