IME, 5 hours is enough time for a quick run into Amsterdam Centraal, I've done it several times. The trains run frequently, are inexpensive (check out the Nederlandse Spoorwegen/Dutch Railways site www.ns.nl for times and prices), and go from the train station under Schiphol. Very convenient.

Things to consider:

• Make sure you get your onward boarding card before leaving the airport, if you don't get it in PRG (you should).
• Put your belongings in the numerous airport lockers around Schiphol. You can pay with euros or credit card (though I'm not sure if you need a European Chip & Pin card or not, it's been a while since I've done this).
• Just make sure you have your passport and boarding card to get back into the airport.
• Research the destinations available from Schiphol on the NS website; I've heard others who've gone to nearby cities instead (I believe Haarlem was mentioned? One place in NL I haven't been so can't comment). Just need to consider that many places will have reduced frequencies so missing your return train could be disastrous. Since it's your wife's first trip and you only have 5 hrs, probably best to stick with Amsterdam.

Any other suggestions?