My middle boys is turning 4 next month, I need ideas to make him feel very special.

My sweetie Devin is turning 4 soon. He is in the middle of 3 boys and at times seems lost. I want him to feel so special this year on his birthday. He loves dinos, transformers, superheros etc. Because he's not of school age he doesn't have a lot of friends yet to invite to a party. What should I do to celebrate his day?