This is an active topic at the moment for us (QOC), and my secret plan is to help promote the concept nationwide (OUSA) eventually, if we can crack the problem at least a little. I readily acknowledge that this may just wind up as yet another one of several sisyphean tasks I've attempted on behalf of orienteering.
So far, we have only publicly deployed (on a trial basis) a widget from
RideAmigos. The QOC Board identified several factors that would be problematic for more widespread adoption of this particular system, so after looking at at least 30 alternatives, we've narrowed down the current investigation to "just" seven others.
If anyone is interested in studying this with us, I'd be happy to share our criteria and assumptions. There's an interesting
website that has been useful, but we are definitely oriented towards a ("non-dynamic") solution that works to get club members to/from events, and not a general "for the public", to/from anywhere, and/or carpooling-to-work type of approach.