Modern Equivalent of "garage startup"

I've been rewatching Halt and Catch Fire (again) and it got me thinking. What's is today's version of a few guys getting together in a garage to build something cool?

I know it's kind of a romanticized notion, but a couple of regular guys can't get together and build a cutting edge piece of technology from scratch, can they? If so what would that look like?

With the connectedness of everything software seems to have been where those types of things were happening most and now with the proliferation of AI . . what's next?