Fun things to do with 3 y.o.?

[AngelDog]

Can anyone suggest some fun things for 2 adults and a 3 year old to do (which won't be hindered by a baby in the sling on my front).

DH has a few rare days off work and we want to do some fun things, probably at home. Usually when we spend time together we are out somewhere but the wet forecast means we'll probably stay at home.

He and I do things together in the week, but I want something that DH and I can both join in with.

DS1 is 3 next week. He enjoys duplo, trains, painting, cooking, reading, numbers. He hates excercise and role-play.

[CharlotteBronteSaurus]

baking?
mine and 2 and 5 and both love baking. Stuff like flapjacks and rocky road especially, as they're less about precision and technique so I can be very hands-off

or make salt dough, cut out shapes/model figures, bake them and paint them

[AngelDog]

Thanks. We tried painting roday by driving toy vehicles through trays of paint - very messy. DH's comment was, "I can see why you don't do more of this sort of thing!"