This is a really useful new website for families in Boston with kids ages 0-5.  The features that I love are:

It has a calendar of free and low-cost events for young families going on in the city.  Everything from story hours at libraries to Frog Pond dates and times, nature programming at the Boston Nature Center, to one-time holiday events, such as the Boson Common Tree lighting or First Night.

There's a developmental milestones guide (in eight languages!) that you can download and print out. It lets your see what kids are doing in each age range and suggests free easy activities you can do to support his or her development.  It's simple, but a nice reminder on things like, "remember to count the stairs," or "let's find all the red things we can on our walk today."  Sometimes I forget the easy stuff.  It also is great as a conversation starter if I have a concern and want to bring it up with the pediatrician or need to be reassured that my child's development is on track.

There are tons of links to lots of fun resources for families in the city.  The categories include childcare, social services, screening and early intervention, school registrations, free and low-cost activities, etc. 

You can sign-up to receive a monthly email or test message with developmental info based on your child's birthday. 

I think this is a "one-stop shop" for parents in Boston and a great "start" page when searching for things to do with the kids or info on development, schools, etc.