Barcelona Children's Day Out

In the Old Port area at the bottom of the Rambla, there is the Aquarium, complete with sharks and giant rodents (and i mean giant) and the Imax 3D cinema complex, surrounded by bars, fast food restaurants and shops. All by the sunny sea, so you can sit and rest your feet in between bouts. Even if it's not sunny, which let's face it, would be difficult. 'They' will be tired out just walking down the Rambla looking at all the street entertainers, so mission accomplished!
http://www.imaxportvell.com/ingles/imax.html

http://www.aquariumbcn.com/AQUARIUM/index.php?wlang=en

If you've got any money or time left, there is the zoo in the Ciutadella park. I've never been but my husband said he used to force his parents to go every single time they went to Barcelona on a day out.
http://www.zoobarcelona.cat/en/home/

Moving inland you've got the amusement park of Tibidabo which can be reached by cable car and tram or bus. After that, you might not need to go on any more rides, and you'll have seen most of Barcelona from a bird's eye view.
http://www.tibidabo.cat/en/info/com-arribar-transport-public

Last but by no means least, and you'll probably need another day, is the CosmoCaixa Science Museum - a really wonderful touchy-feely, sticky hands-on museum, highly recommended. A very good rainy day destination. Unfortunately the website is absolute rubbish in English. Completely impossible to find the information you want, typical of a bank. Suffice to say it costs 3€, free on the first Sunday of the month, closed Mondays. Opens at 10am til 8pm. Open on holidays and holiday Mondays. Not Christmas day or New Year's Day. Address is C/ Isaac Newton, 26.
http://obrasocial.lacaixa.es/nuestroscentros/cosmocaixabarcelona/infoservicios_es.html

The Chocolate Museum. Well, we enjoyed it! 

http://www.museuxocolata.cat/?lang=enHere is a link for a Chocolate Tour of 2 hours run by the tourist office and it is a walk around the gothic quarter.
http://bcnshop.barcelonaturisme.com/ECV2TBCN/Front/BCNShop/Sales/Disponibilitat-Producte/_vf-SMlY1yItM-U_l9RgLJgsyU0uRJi84RqTVW4Qu8jlwlsbljT_nJMKtbrFTKhdgfLI1AsrLkWTMA-NoR99VR5sKtu1cV9yVaEIyon7WyN4cvKkgoJpmRJ9VUx9dzhkP
This is a Segway tour but i am not sure what the minimum age is for children.....i am obviously not responsible parent material....but could be fun?!
http://bcnshop.barcelonaturisme.com/Barcelona-Segway-Tour/_vf-SMlY1yIuKQTV1aq49kDeqxRqjploriWCdo8IR0jKVDOZqQnrzvcItaEElOLAI

(I think that's enough children's stuff - who's going to pay for all this? ed.)