Prague for 12 days.

Tina -- I was there in November 2009. We took a tour out to Terrizin Concentration Camp, which was very interesting. The hotel provided the information about the tour -- and it was well worth the time and money. Takes a good day to make the trip and see everything. You will love Prague. It is so beautiful. Wonder across the Charles Bridge, spend some time in Old Town -- and just be careful of the cabs (per Rick Steves' good warning).

I would recommend a day trip to Kutna Hora. You could do a tour with a small group in a mini van or similar.

The Jewish cemetery is a must see.

Just back, had six nights seven days in Prague. We stayed at the Kinsky Garden Hotel which is several blocks from the Charles Bridge. We (and seemingly hundreds of others) basically walked everywhere, from the hills of the Palace to the Old Town, Jewish Quarter to New Town, down to the free Botanical Gardens, but trams are everywhere and cheap,if you can figure out the tickets!. My college daughter is doing a semester there, and feels that it's pretty safe. We did go on a day trip to Terezin, the concentration camp, and almost went to Plzen (the birthplace of pilsner beer?) but it was pouring rain. A few things to know: better have plenty of Czech change to use the WC anywhere; divide Cz costs by ~20 (ie 100 Cz~US$5); soda is cheap but the bottles are about 4 or 6 oz, not 8; not many speak English but most folks give it a good try; Czech common cuisine seems to be about cured meats and great beer; have good shoes because the paving is frequently uneven. [About the toilets/WC: even in the oldest ancient buildings, some of the facilities are surprisingly modern and clean!] Rick's book is a very handy guide. Have fun!

In my opinion, 12 days in Prague is way too much... you can get to so many great places from there though! Vienna is 4 hours by train and Berlin is ~5 hours by train.

I've not been to Berlin, but I can tell you that Vienna is just great! Great museums, great cuisine, great operas, etc. Check out Wikitravel to find out more.

Additionally, I didn't have the chance to do this, but I know that Bratislava is also an hour away, and perhaps you could also go there while visiting Vienna as well.

I would really suggest that you go visit Vienna for a few days instead of staying in Prague all 12 of those days. I personally am not a fan of Prague; I find it to be way too touristy, but if that's your thing, maybe you'll enjoy it more than I did.

It's great you are going to Prague but must be a bummer to have one of you tied up for a week for training during the day. I don't know your travel experience level or your interests. A person that is a newbie at int'l travel & timid of going it alone should take a walking tour to get an overview. To start out, there's a "free" 3 hr tour of Prague at 11am every day you can look at on www.newpraguetours.com. If you feel the tour was good you can tip how you see fit when it is done. And it will give you many ideas of places to go back to and see in depth. Vysehrad is a place to take a look at in Prague that most folks don't seem to go to. I would try to get out of town with your sweetie on days he is not training. One must see is Cesky Krumlov. They have the five petal rose festival going on each June around the summer solstice which is pretty good. Make sure you try to get a place to stay there now for overnight if you want to do that as it is quite packed.

Thanks everyone for the great information. Planning, planning, planning!