7 Nights in Prague - Suggestions for Activities?

http://www.parkpruhonice.cz/index.php?site=en
this is one of my favourite places to visit, just outside of Prague , you can get there in under an hour by public transport from central Prague .I am visiting there again in just over a weeks time.
http://www.lidice-memorial.cz/en/
the Lidice memorial is a very sad but interesting place to visit, read up on the Reinhard Heydrich assassination to get the background to what happened there.
http://www.prague.net/
this website might give you some ideas.
In the good weather I like to visit the parks and especially the beer gardens in the Parks.Lenta and reigrovy sady both have excellent beer gardens and are nice parks to visit in the own right.
Stromovka park is also a lovely place for a stroll.You can take the bus out to the Zoo and to Troja chateau and walk through the park back to the city,there are a couple of cafes/bars within the park to stop for refreshment. There is also a boat trip you can take to and or from the Zoo/Troja.
info on this website.
http://www.praguesteamboats.com/
hope this gives you some ideas.

Day trips to Terezin Concentration Camp, Kutna Hora's Bone Church and tour of Silver Mine.

whilst I am on a roll. you could take the fenicular up to Petrin tower visit there then walk through the park to the Strahov monastery, worth visiting the Library there and there are several other things to see including a minatures museum (I personally have never been in the that museum). down from Strahov is the Loreto building that is also worth a visit.

yes Terezin is worth a day trip easy to do on your own and Kutna Hora is also easy to do yourselves.

For a day trip you can also consider one of the castles nearby Prague: Karlstejn, Krivoklat, Konopiste. They are all in Rick Steves book: Prague & the Czech Republic.

Thanks all! Will certainly look these options up!

I would recommend going to the Mucha museum. Amazing art and worth a visit. I didn't see that mentioned yet. Also, in the evening you could attend a concert or go to a Black Light Theater. A trip to Cesky makes a great side trip if you want to see a small town after being in Prague.

I assume that Jenn by writing Cesky means Cesky Krumlov. In that case I would recommend overnight. It takes 3 hours one way. Cesky means Bohemian (unlike Moravian- yes there is Moravsky Krumlov) or Czech.
There are 17 towns in the Czech R. starting with Cesky. I would mention just few which could be worth visit: Cesky Sternberk - much closer to Prague than C.K. Easy as a day trip from Prague. There is an impressive castle on the cliff there.
http://www.hradceskysternberk.cz/introduction.html
Then there is a little untouristy town Cesky Brod very close to Prague, easy to get to by train.
http://en.wikipedia.org/wiki/Cesky_Brod
Cesky Dub in north Bohemia, little farther from Prague but still closer than Cesky Krumlov.
http://www.cdub.cz/turistika/
The largest town of Cesky is Cesky Tesin. On the Polish border, close to Slovakia.
http://en.wikipedia.org/wiki/Cesky_Tes%C3%ADn
If I don't want to write Cesky Krumlov I can write C. Krumlov.

I loved my time in Cesky Krumlov and if you want to leave the city would spend 1 night there. A couple times we did a marionette show and it was very interesting... Also, have to second the Mucha museum, but he is one of my favorite artists. I also searched out the house where Kafka lived. I got up really early one morning (4am) and walked down to the Charles Bridge to watch the sunrise. It was spectacular and I had the place almost to myself. I am a photographer, so it was really special. When we returned later in the day it was packed with tourists and it was not even like the same place. You really don't need to go off the beaten path, you just need to try and see some of the city when it is not overwhelmed by tourists.
I went to Kunta Hora, as I had a friend who was intrigued by it.... just plain creepy to me and I would not need to return.

There's lots of great music and performance for your evenings. Catch an opera or concert at the Narodni Divadlo (National Theatre). Prague Shakespeare Company (in English!!) performs at the Estates Theatre and other venues. Skip the Black Light offerings.