Our first activity was working with a set of flash cards I bought on EBay. On one side the card has a number and on the back it has pictures. J would pick a card and I'd show him the number side and say the number. Then I turned the card over and J and I would count the items as we pointed to them. This was an OK activity for him, but we didn't do it for a long time.
These are the counting books that I picked out to read. J and I would read the book together and again he'd point to the items and then we'd count them. He really liked the reading part.
Our last activity was working with stringing beads. J would attempt to put the lace through the hole in the bead, but often would need a little help from me. As I helped push the lace through the hole, he'd grab it and pull the lace through. Once he had several beads threaded onto the lace, we would count them.