I will have to take care of my two little cousins (6 and 4 y.o.) for the whole day on Saturday May 1st and the weather forecast seems to be quite convinced it is going to be a rainy day

We cannot stay at my place or at their house (they are moving that day, that's why I have them), so I need to find something to do

Any suggestion is welcome!!!

same problem with me, rather us......and it is even worse they are my children!!!!I thought might take them out swimming or to Kindercity at Volketswil they are open that day.

Take them on a long train ride ( a train that has the Family Section eg Zurich Hbf to Romanshorn or Zurich Hbf to Brig ).

You might also wish to consider visiting the Tram Museum ( http://www.tram-museum.ch/content.php?id=3 )

or

Technorama ( http://www.technorama.ch/index.php?id=2&L=1 )

or Starbie Dietikon
( http://www.starbie.ch/index2.html )

or

Aathal Dino Museum
( http://www.zurichtourism.ch/en/page....region&id=4874 )

Whatever you do, check that it is open on May 1st before you set out.

I found a flyer this morning, given out by the one of the Zürich Sites. There is one section on things to do with children. Maybe you could get an idea from there.