Amsterdam Zoo is very nice. It's within a few kms of the center of the city, and also has a marine section which is very big and has all sorts of fish etc. Then there's load of animals too.
The Heiniken factory is there.. never got a chance to look at it.
Coffee shops all over the place.
Loads of museums, including the Anne Frank museum.
The red light district is large but perhaps a little seedy but not as much as you might expect.. but that sort of thing will always attract undesirables.. as long as you're not completely stupid you'll be ok (imo), even at night. I think most Irish people would be very surprised at the type of women behind some of the red lights.
Nightclubs and raves open until the early hours.
You might be best getting a hotel near Central Station, as then getting to and from the airport is easy... and obviously central station is central. Airport is 20km or more from the city, but 7 Euros or so on the train. If your train carraige is carpeted then you're in first class and you likely don't have the correct ticket. It's 'self assesed' if you like, which works in Europe. There will also be ticket checkers.