This is super cool: EuroVelo, European Cycle Route Network or Sustrans EuroVelo.

EuroVelo, the European cycle route network, is a project of the European Cyclists' Federation to develop 12 long-distance cycle routes crossing the whole continent of Europe. The total length of these routes is over 60,000 km, of which more than 20,000 km is in place.
The planned routes would apparently include 30 countries throughout Europe. Looking at that map makes the balls of my feet itch to clip in. Anyone up for a holiday in Europe?