Ah, I only mentioned the idle thing because you also mentioned folding@home (which at least seems like a good use of the cycles; I remember in the 90s there was

Ah, I only mentioned the idle thing because you also mentioned folding@home (which at least seems like a good use of the cycles; I remember in the 90s there was a thing where people used their idle cycles to break an RC5 key just as a contest). As for FPGAs and MATLAB: They are not necessarily for the same hobby, but one hobby that not only uses both, but also benefits from my computer's power is DSP (i.e. Digital Signal Processing). As an example, I made both encoders and decoders for NTSC and PAL. I use MATLAB for other stuff too, though, for example for analog electronics. Designing filters, characterizing feedback loops and so on. No FPGA in that case.