Must do a free walking tour. The one I took was awesome, a 10 dollar tip is customary.

You started it............ Lol

Awesome city, I'm off back there myself soon and can't wait. Not sure of your tastes, where you are staying or if you've been before so here's some stuff I enjoyed.

In you are staying around the North East of the city then Prenzlauer Berg has loads of great bars in Schönhauser Allee which is the main street. Check out White Trash Fast Food for bands and just over the road is a great bar called 8mm that shows films with Bassy Club next door which usually has something good going on. There's loads of other great bars around there, well worth a wander. The TV Tower, Fernsehturm, is just down from there and gives nice views of the vity but if it's a weekend you might have a 20 minute queue then have to come back 90 minutes later to go up.

If you've not been before I'm sure you'll certainly be going to the East Side Gallery to check out the graffiti on the wall so if it's a nice day check out Yaam whilst you are there near one of the big remaining stretches, it's an awesome sandy Caribbean beach bar overlooking the river right in the middle of Berlin. You'll probably find it by following the music you hear whilst wandering roung the east side gallery. Not sure if you are interested in the more usual tourist destinations such as Checkpoint Charlie, the DDR museum etc but all well worth a visit.

If you are there on a Sunday then there’s an amazing park called Mauer Park which has crazy outdoor karaoke on a massive stage with thousands of people watching – I hate karaoke more than anything in the world and I enjoyed it so that’s how good it is! There loads of bands and drummers and people making noise as the evening draws in that gives it a sort of festival vibe so it's a great place to come and chill with a picnic on a Sunday.

If you like football then if they are home go see Herta Berlin at the Olympic Stadium for the experience as it’s dirt cheap (14 euros a ticket plus there's often 25% off vouchers)

There's lots of stuff I wanted to do but just haven't had time yet, especially the old abandoned theme park called Spreepark which looks amazing in a Scooby Doo sort of way. It used to be a case of jumping the fence and avoiding security but there's actual organised tours these days.

Or you can just forget all that stuff and get hammered as there’s cool bars everywhere.

Price wise it is pretty reasonable, probably about the same as eating out in most cities in the UK. Beers are about 3-4 euros each, beers from off licences etc are dirt cheap. The Berlin welcome card is worth getting as it gives you which gives you unlimited train/underground travel and discount off most things (normally about 25%) for about 22 euros each.

Hope that helps, if you want any more info just drop me a line

Glad your trip was good, have to admit I've never been to Berlin.  If you could post some of your images when you get a chance I'd be grateful.

Yeah my wife spotted that one, got a photo (that was a different one)

Edit:
Hang about that was urban spree, we went there on the Monday night for some beers and watched local film makers short films on Berlin, in a old warehouse, great atmosphere

You should definitely check out the Urban Nation Museum.
Its free and they have some amazing works: urban-nation.com
If you walk a bit around the museum you will find lots of nice works on the streets.
Not so far from the museum on Bülowstrasse there is a huge mural by DFace & Shepard Fairey.


Next thing you should check out is Urban Spree and and the RAW-Area where you will tons of works by international artists as well. In walking distance is also Oppelner Str. where you will find The Yellow Man mural by OS Gemeos. There used to be a few pieces by Stik in this area too, but I think most of them are not there anymore.