If you have always wanted to play tourist hopping on and off at tourist destinations in Prague while riding on one of the historic trams, you will be able to this summer for a 200 CZK all day ticket.  Tram 42 is more than 100 years old and will be taken out of retirement for a fun experience.  While you are at it, take the opportunity to visit the public transport museum in Střešovice, Prague 6 where you can see other lovely retired old historic trams.