you could start here:

mimoa

archinform

nextroom paris

nextroom london

nextroom prague

nextroom wien

nextroom amsterdam

check previous discussions, it's been brought up several times.

Some good galleries in London are free: British National museum, Tates, and make sure to carry student id.
When was in Netherlands, I went to Utrecht to see Schroder House and it was very much worthwhile. In Amsterdam, Van Gogh was good, but i wasn't that impressed with Rijks. Rembrandt and Anne Frank's house are good places to go. Watch out for pickpocketers in Amsterdam... I got pickpocked and totally miserable for couple days.

There are many threads on London, though I'm not sure if I mentioned these:

In London:

Parasol Unit for Charles Avery (the show could well have been titled "If Borges could draw")

176projectspace is a magnificent space with one of the best exhibitions I have seen in years.

Established & Sons furniture makers

Lounge Lover for expensive drinking, Yauatcha for tea and cakes, Flat White for coffee.

It's sometimes worth checking the London Architecture Diary for events, and the Bartlett List too.


In Paris

Musee de la cité et du patrimoine
Koons @ Versailles, causing riots
Musée Antoine Bourdelle (Christian de Partzamparc)