hi indydad,

glad to see that the Deutscheshistorischesmuseum is on your itinerary - one of the best we've ever been to anywhere, but that may be because of the exhibitions that it had on at the time we were there of course.

what you may also enjoy is the area around the Fischerinsel -[ where you are staying] which is a canal area with little bars and cafes, and the Nicolaiviertel [viertel = area] across the river -the walk around that area is interesting as is the 1 hour boat trip that you can do around the centre.

a little bit further on is the Fernsehturm in Alexanderplatz - http://www.tv-turm.de/en/

wonderful views over the city and a great revolving restaurant which your kids would love- reservations required though.

for a nice meal and good beer, I can recommend this place just across the river from your hotel:

http://www.brauhaus-georgbraeu.de/

i can absolutely promise you that you won't run out of things to do !

just bookmarking

You need to be aware that Good Friday, Easter Sunday and Easter Monday are all holidays, and things may be closed. Friday is considered a "quiet" day, there will be very little public life.

Not sure if your itinerary for the 30th will keep you busy all day - even at a leisurly pace.
You may find time (and energy) to end your day at Wall memorial site, just a few stops by S-Bahn from Brandenburg Gate.
The Museum at Checkpoint Charlie will probably keep your kids entertained, but in general it is more a rather compact, or cramped museum with artefacts from often hilarious attempt to get across or over or under the wall. So you won't exactly get a "real" feeling for what the wall and death strip looked like there other then pictures. If you look for such, you should swap it for the Wall memorial site.

The boat trip which PP mentioned is a nice idea to see the sights of the Mitte district and get off your feet for an hour. If the weather plays along.

In general you should also keep an eye on the local TI website visitberlin.com so you won't miss any temporary exhibitions or activities which you might like.

Greenway mentioned a good point.
While most sights you mentioned should be open all holidays (with Good Friday being the possible exception), stores will be closed Easter Sunday and Monday.
Though neither Good Friday or the Easter days will effect restaurants, cafes, bars or pubs. As everybody in Germany got a long free weekend from Friday to Monday, and Berlin is also a hotspot for domestic tourism, you can expect a LOT of public life on either day. Except for shopping, which will only be possible on Saturday with the exception of the tourist/souvenir shops near the major sights.

Another vote here for the German History Tour. The audio is worth it too.
Here is a recent post from this board that covers much of what you are interested in http://www.fodors.com/community/europe/berlin-with-dresden-trip-report.cfm
The walking tours are very good value for money although I'd steer clear of the "free" ones. They work for tips. The guides for the commercial operations are likely to be well informed.
Checkpoint Charlie, aside from the museum, is worth about 10 minutes. Be aware that the very popular museum there is a private operation. Background here http://en.wikipedia.org/wiki/Checkpoint_Charlie_Museum
The tiny inspection station on the street, and guards, are fake. Actors also set up for photos at Brandenburg although there is enough around there for an hour.
Berlin is a wonderful city for anyone with a curious mind, especially young teens who don't mind walking.

PS: Would your young folk think this place is a treat? I can't speak from personal experience so I don't know how much of it is for techno freaks and how much for games players:
http://www.computerspielemuseum.de/1210_Home.htm

Another long Fodor post is here: http://www.fodors.com/community/europe/5-days-in-berlin-sept-12-loved-it-long-trip-report.cfm

Thanks for the comments -- keep them coming.

re: closings.

I *think* most of the museums, public transportation, and hopefully restaurants are open. Shopping's not high on the list but it is good to know. I guess it may also curtail some options for picnic lunch preparations.

re: Checkpoint Charlie.

Decidedly mixed reviews from what I can tell. We'll play it by ear.

re: Saturday

Thanks for the feedback, Cowboy. I'll be sure to have some stretch goals in mind in case we have time on our hands

re: Trip reports

Thanks for the links, Southam. I've come across those previously, but it's a good reminder to review.

re: restaurants.

Thanks, annhig. Always appreciated. I haven't started thinking about those yet -- you've given me a good start.

Thanks, annhig. Always appreciated. I haven't started thinking about those yet -- you've given me a good start.>

food - always my starting point and specialist subject.

BTW - the Fernsehturm is worth seeing in its own right but the restaurant is the icing on the cake!

You can find the memorial to the bookburning at the Bebelplatz. You look through a plexiglass window into a room of empty shelves. It's simple but effective.