While everything else is a bit shit I had a bit of fun with some old beaten up classical guitars I got hold of. Pulled the frets of one and converted it to a fretless - certainly not a top notch result but it plays, holds tuning (mostly) and is an extra challenge. Got another one which I'll probably do the same too eventually - but with more care.
https://www.youtube.com/watch?v=r3hB5HPq_lM