How to make him feel "special"?

Help me think of some special things I can do with my middle child.

I feel like Aiden tends to kind of take a backseat to my other kids/kid. Of course there's the whole "middle child syndrome" (as people call it). But on top of that, when Seth was here it was all about him, naturally, because he was sick for almost a year. Shortly after he passed away, we had to switch focus to my daughter and concerns for her development/autism.

But I don't like him feeling left out, and I know he does often.

Give me some ideas. What are some things (that don't cost money, preferably) I can do especially for him?

Can you go on a "date" with him? I take DS out once a month, with just me, him and SO. We go a get a food he likes- which usually is not terribly expensive. Then the movie theater near us plays kids movies for $1 entry once in a while, so we go to that. Or we go to the park, or the children's museum, or the zoo (because we have year passes.)
It really helps him feel more involved, and gives him back some of that attention he has lost.

Quoting Jo&M:" Can you go on a "date" with him? I take DS out once a month, with just me, him and SO. We go a get a ... [snip!] ... (because we have year passes.) It really helps him feel more involved, and gives him back some of that attention he has lost."

 
Or you could get a movie to watch at home and make it like his special night ever so often. Do a movie, snacks and maybe a game with just you and him.