It's called goseedo.com and lists all sorts of things for you to do and places for you to visit (either in this country or others) if you're stuck for ideas; I've had a quick click around it and it looks rather good.
If you're really stuck for ideas there's an 'Inspire Me' option - simply click it, click on the image that appeals to you and a whole host of ideas will be at your fingertips.
You can search by location, within the UK or by country - you're not limited to ideas for single summer holiday days, if you're looking for a family holiday that's perhaps a bit different, or somewhere in the world you might not normally have considered, then goseedo.com can help you out as well.
Categories include: Theme Parks, City Tours, Day Trips and Water Parks etc; Themes searches include: Sightseeing, Food and Drink, Once In A Lifetime, Thrill Seekers and Family Fun.
If you find something you'd like to do - a flight on the London Eye perhaps? - then you can book online through goseedo.com as well.
I think this is a lovely new little resource for parents and I'm sure it will grow and grow and become more and more popular.