I've been to the zoo in Warsaw 3 times which is not a bad attendance record for 4 years living in the city. It's a nice place to spend a warm afternoon, preferably on a weekday in May or September when the kids are at school and you have the place largely to yourself. At 100 acres, the zoo is quite large and whilst not as big as Europe's largest zoo in Chorzow (Southern Poland), it is nearly 3 times the size of London zoo and 5 times the size of Cologne zoo.
Entrance is 15zl (£3) for adults and 10zl (£2) for children, which really isn't bad at all. There are two entrance gates both located in the cities Praga region which if you believe most Varsovians houses plenty of people who think they are animals too! There are maps throughout the park, names are in several languages including Polish, English and Latin and there are colourful charts showing where the animal's natural habitat is. Further information about the animal is only available in Polish though.
All the big animals you expect to see are there - Camels, Elephants, Rhino, Kangaroos, Polar Bears, Leopards and of course the sleepy lions who have a rocky hill to while away the hours. There are plenty of other interesting looking critters and in particular some good jungle like walkthrough chambers featuring birds, crocodiles and other reptiles. There is a nice monkey den as well as a nice hang-out for Poland's beloved Zubr (European Bison). It's not just wild animals though, there's also an area particularly popular with children dedicated to more domesticated animals such as rabbits, rare breeds of goats, sheep and the noisy donkey!
There are a few souvenir shops, several toilet stops and numerous pubs and cafes where you can have a beer, coke or something to eat. There are also a few stalls selling candy floss and popcorn. This is a great place to spend a day and really quite affordable, kids will love it and there are little carts which sit children and can be pulled behind by the adults. Likewise there are bicycles available for those who don't want to walk.