Roosevelt Island is one of New York's awesome hidden gems. One of my favorite things to do when the weather is nice is take the tram over the East River and grab picnic supplies from River Walk Bar and Grill. This restaurant has an amazing staff (when our order took a little longer than usual, they gave us free drinks while we waited) and they'll pack you a picnic bag full of fresh salads, sandwiches and a bottle of wine. Take a walk around the island and find a nice spot (there's a great park in the middle of the island) and when you're done, drop off the bag and head home. It's a great way to see some New York history and get fresh air on a nice day.