Well, every year it seems like we get a week in March that is really warm and beautiful and then by late March, when the kids are on spring break, it turns cold and rainy.
Expect rain and a chill to the air with the potential for some pretty spring days. Things won't quite be green, but all of the bare trees will be just about ready to leaf out. Some people will have green lawns. The forsythia will be blooming and some early blooming trees could be beginning to blossom.
As for must-do items, do search the forum a bit. There are a lot of threads that address this that have been written over the past 6-12 months. Good luck to you!