I'm pretty lucky in that we have one child and live in London which has a gazillion things to do. Until DD (3.5) went to full-time pre-school, I was a SAHM and now run my own business from home.
Must admit I've never been bored (other than pushing swings). We tend to take DD out to museums at weekends or other places in London. Harrods for example is a great cheap day out - the other week they had free face-painting, free balloon animal things, free nail painting, glitter tattoos etc. The kids can also actually play with the toys on displat. DD is pretty good at not wanting to buy everything there and enjoys it. In the meantime DH or I have a wander to look at things that interest us (you can even have free coffee at the nespresso capsule counter).
I refuse to watch horrible kids TV, so DD doesn't know that things like Disney's Cinderella exist, nor has she even seen Dora. Instead she has things like Mary Poppins, Chitty Chitty Bang Bang, Narnia and HP. She loves them, but is also a child who is utterly fearless - she thinks the child catcher in CCBB is amusing, I was terrified of him as a child. She understands the plots, loves the songs and dance routines and I can actually cope with watching them a gazillion times a week.
They also tie in well with museums - she likes to play in the Anderson shelter in the Imperial War Museum because it's like the beginning of the Lion, the Witch and the Wardrobe.
In nice weather we go for walks or go to the park to feed the squirrels. DH has adopted photography as a serious hobby (poor DD is the most spied on kid I know) so he has something to concentrate on when we are out in terms of improving his technique, experimenting with different ideas.
I firmly believe that children should have plenty of time to amuse themselves. If we have gone out for a Saturday to a museum or something like that, then when we get home it is 'Mummy and Daddy Time' and DD is expected to play nicely with her toys and entertain herself while we read or play with the computer or even just have a nice quiet child-free bath.