I found this info on another blog and thought it was pretty cool:

the International Space Station. The ISS was originally conceived as a staging base for trips to the moon or to mars, cuz after you've achieved orbital velocity, you're already more than half way to escape velocity. However, the nature of the ISS changed when we (the U.S) decided to include the Russians. This was largely a political decision; to encourage political ties, but also to keep the former Soviet rocket scientists busy so they wouldn't turn their attention to nukes. However, when they decided to include the Russians, they had to put the station into a high inclination orbit (closer to around the poles than just the equator) that renders it pretty useless for interplanetary travel. A plus though, is that we get to use their launch sites to re-supply the ISS also. It's a tradeoff either way, but the ISS no longer serves its original purpose.