Countdown to Europe

Ok, my schedule is getting finalized.  Most of my bookings have been done, so I'm less worried now.  I've decided to take 1 vacation day before and after my 1-week business trip, so that I can have a full weekend in London and another full weekend in Paris.  I've never been to Europe and I know 2 weekends won't be enough, but it's a start.  I usually don't give my xy-coordinates in real-time, but I'd like some input.

• Thurs, March 30th - depart from US (woo hoo)
• Fri, March 31st - arrive in London, spend the weekend in London
• Mon, April 3rd - work in Cambridge for 2 days, then fly to Holland
• Wed, April 5th - work in Holland, Netherlands
• Thurs, April 6th - work in Cambridge, then fly to Lyon, France
• Fri, April 7th - work in Lyon, then take train to Paris, spend the weekend in Paris
• Mon, April 10th - fly back to the US (boo hoo)

Now I just need to decide what to do with my weekends, i.e. typical touristy stuff like museums and of course some European clubbing.  I am meeting up some friends in London and Paris, so I'm excited to have a personal tour guide, especially one who speaks French.  So much to do, so much to see, in so little time!  Suggestions on what to do in my comment box below would be much appreciated.