What trackballs can I use on the Towns? I have a marty and HR20, would love to play some marble madness with a trackball.
These guys (https://www.ebay.com/itm/111546333739?hash=item19f8adfa2b:g:VDEAAOxyni9TA7II) have been on eBay for years and if you can track down a PS/2 trackball (scarce these days but doable) it should do what you need.
The item in question is from a little indie outfit called KMTech, named for the solo engineer Kevin Mount who makes the gear. There's also a USB equivalent component that's available:
https://newstuffforoldstuff.com/display_product.py?pid=75
As moderator, I want to encourage everybody to describe links in detail and provide information about sources and URL destinations. 'These guys' is not properly descriptive text, especially when someone is looking up the information ten years after the fact and the link has died. To be clear, nobody has done anything wrong here, but I want to make sure that everybody who's contributing makes a lasting impact for both the present and the future of the forum.
eBay is really nasty about everything these days, but among the the worst offenses is how they demand you not embed any links to external sites in your listings. Because of that I forgot the people making those adaptors had their own site!