I really love it when people carry jokes into serious business and take it all the way to the end. There's a lot of guts in that. I envy that level of self-confidence and hope to one day get there myself.
That said, somehow I love it even more when such jokes get featured on HN and, invariably, shares of dry humorless grumpy people complain that they can't possibly take people who make jokes seriously. I always wonder what brings someone to distrust ballsy humor, I can't really wrap my head around it.
Personally, if someone has the guts to not only make a silly joke with friends over a beer, but actually turn it into a real thing (in this case, a venture fund), then that's the kind of person I want to do business with. That sort of guts shows elsewhere too (Elon Musk is a nice example).