e-carpool
While this site is useful for connecting European commuters, it can also be an invaluable resource for foreign visitors looking for a cheaper mode of transportation. This is especially true because it is not easy to network and establish your rideshare from abroad. e-carpool is constructed in a way that supports one-off trips that a foreign traveler would be interested in. You can access this site at either e-carpool.eu or e-carpool.net