I must admit that rather than focus upon other technologies (Raspberry PI, etc.), I am much more intrested in keeping older Mac computers going, and collecting the Macs that I've owned in the past. I have noticed that it's actually getting harder to find genuinely working Macs on sites such as eBay, where more and more machines are sold 'As Is' (i.e. not working, but not describing them as such), for really quite high prices, even higher when they are demonstrably working and one of the more popular models (such as the original tangerine or bondi G3 iBooks). I have searched often for a Colour Classic, as sold in Europe c.1993, and aside from outrageously priced 'Mystic' models, there really isn't much out there (on the UK market, at least). But this is one that I would reall like to find, as I completed my whole undergraduate degree on (I went to college at 33). I'd also like to find a working PowerBook 5300, as I had one of those through my master's degree and early doctorate, before switching to a PowerBook 1400cs, 166Mhz (which I have found on eBay a little while ago, though only with the floppy disc drive and no clear, Perspex cover, though otherwise fine). I still have my PowerBook G3 'Pismo' (working on it now) and my iBook G4, a PowerBook G4 15", 5,2 (though the second memory slot is a bust), and a 2009 iMac.
So, the next unit remains finding an elusive Colour Classic that I once had and that, sadly, stopped working back in 2010 (and I hadn't the skills to repair it)…