The 7 yo had problems with planning, spatial orientation, sequencing and fine motor manipulatives.
He also disliked occupational therapy.
On the other hand, he liked the idea of working with Lego, even though he couldn't complete the simplest project. So we enrolled him in the Lego school of occupational therapy. Heck, it was vastly cheaper anyway.
We've been working on our Lego projects for a bit over 2 years now. At first I did everything but push the piece into place. Then I would select the piece and orient the target and the piece, silently pointing out where it ought to go. Then I'd select a piece and point to the diagram. Then I'd present a piece and point nowhere. Then two pieces. Then all the pieces for a given "move".
Abruptly, I didn't need to select anything at all. My only role was to scratch his back.
Today, he completed the last third of Indiana Jones and the Temple of the Crystal Skull (age 8-14, he's 9). I was called down for two consultations, including locating a dropped piece.
The Lego School of Asperger's OT probably cost us $600 or so over the years, but at least 2/3 of that was spent on birthday and Christmas presents and some rewards for special achievements. It was also great fun for both of us.