I'm gathering information on Europe because my husband and I plan to spend some time there in Summer 2009.

So, queries:

1) Have you visited Europe? Where did you stay? What did you do?

2) Has anyone stayed at a hostel? Any recommendations on that?

3) Do people tip in Europe?!

4) Anyone fly from the US west coast to Europe recently? How much was an airline ticket?

5) Someone explain this "rail pass" thing to me?

6) Other information. Tell it to me.

ETA: I'm mostly interested in money-related info and specifics, like where to sleep.