So what do I do???

So I am finding myself having a hard time coming up with things to do with Andrew on a day to day basis. I mean on a nice day I am pretty good. We go for walks, ride bikes, play outside, parks, pool, sprinkler, nature walks etc. On rainy days.... NO IDEA!!! I have tried some of the crafty stuff like coloring or finger paints or anything like that and I spend 20 min setting things up and getting it ready for him to play with it for like a millisecond. He just has very little interest in that stuff. If I keep him in my house, he drives the dogs CRAZY!!!
I have worked with children for years but I just don't know what to do with him. I think it is an age thing. I don't have any playdates set up for today, nothing is good on the gymboree schedule for today (btw we are signed up for 2 classes in the summer). I could go to the museum but they have this huge outdoor thing now and he knows about it and wants to go straight there now.
ARGH, this is going to be a long summer. I really need to figure out some more activities to do with him otherwise this is going to be a VERY LONG SUMMER!!

Oh and what doesn't help is Kevin is working crazy long hours all week. I am totally on my own this week and well I am just not used to that at all!