What could you do with your loved one with Alzheimer's to have fun with them?

I don't know what stage Alzheimers you're dealing with but my FIL is late 5-6. I bought him some music CDs old country music and he loves to listen to this. I also play games with him Jenga, Yahtzee. I have to help him play these games explaining several times what to do next but he seems to have fun playing them. He likes to read westerns, he might read the same page several times but seems content. When the weather is nice I take him outside and we go for a short stroll. It is sometimes a battle to convince him how nice it is but if he refuses we simply try next time. I bought some large piece jigsaw puzzle with few pieces but he doesn't seem to like doing that but someone else might. These are just a few suggestions to try.

We take my FIL outside and just sit in garage for awhile to get outside. He loves his tools, so we get some tools and his toolbox out, some plastic containers and let him sort his things.

He loves to go for drives, even if we travel the same route over and over...we just point out his favorite restaurant, church, barber, neighbors house, etc.

We get out photo albums and reminisce.
He also likes music and likes to hear christmas music or music from the 40s and 50s which we can tune in from cable TV or Pandora.

Remain flexible. Short activities in the late morning are best for him and my mom (dementia). If we get out and about and he seems tired and disengaged, we turn around and return home. I take their lead.
Sometimes, I get carry out, Chinese, etc and we just picnic at home...eating in the living room at a card table, eating on the back deck in good weather, etc...just for an "adventure".

My mom loves to drive around with me...she never tires of the same places and taking different side streets. Everyday can be new experience for them.

Keep activities simple and short. Attention spans are short and ALZ tend to frustrate easily. Also, keep them in routine and work the new activities around those routines.