My nephew J recently turned 3.
One of his favorite things is the New York subway system -- he loves identifying the subway lines and trains and calling out the numbers and letters. He is a city boy from Queens living on the 7 line. Here are some NY subway themed party favors I made:
I found these M&M candy containers at Economy Candy store in the Lower East Side (the best candy store in Manhattan, the antidote to Dylan's candy shop down the street from where I live). The colors match perfectly with the subway lines. I just cut out letters for the subway lines from adhesive paper and stuck them to the tins.
Each guest also got a small candy bag with gummy letters (for various subway lines: A, C, E, B, Q, F, N, R, W, etc!) and a gummy (subway) rat.
My sister came up with the idea to get these subway line refrigerator magnets from the MTA store. Each family got one that matched their name.
The magnets, gummies and M&M's went in small kraft bags and were sealed up with bright yellow tape and a custom label.
My amazing and creative sister completed the subway theme by making subway line party hats and cupcakes (yes, she DID make five different kinds of frosting!). The kids loved it and my nephew's mouth was purple the rest of the day from the 7-line cupcake.