A Princess Playhouse for my two girls.
I should also add that I'm an electronics tinkerer/computer geek, this was my first construction project. I had great help from my Dad and lots of good advice from friends and the Internet. It took me 8 months. So if I can do it, so can you with the right help.
Yes I know, it's a little over the top, but if you're going to spoil your girls you might as well do it right :-)
Rough breakdown of the costs:
8x8 concrete slab - $200
wood and internal trim - $200
electrical wiring and panel - $100
speaker wire and in wall speakers - $100
roof shingles and flashing - $150
drywall - I paid someone to hang and mud the drywall $400
tv mount and tv - $150
vintage light scounces- $80
foam panel insulation - $80
pergo floor - $120
custom sized windows - $200
see http://diymagicmirror.com for parts and costs for the magic mirror
After some Googling for playhouse plans, this one fit the bill, http://www.woodmanor.net/Little-miss-playhouse-plans.html The dimensions are 8x8x8 feet.
My Dad framed it in Oregon, took it apart, and then drove it down to my place in California where we assembled it together.