Any ideas for quiet toddler entertainment?

What to do with a toddler (coming up for 3) in the afternoons at home while the baby naps downstairs? Needs to be quiet so as not to wake her up.

She naps in the pushchair, so I suppose we could go out at least sometimes, but that's not always appealing in autumn / winter weather, and the room we're mostly in has carpet (although I'd love to replace it) so crafty things are not ideal. We do a bit of cooking sometimes, so ideas, or sources of ideas in that direction might be useful.

How about duplo, train set or cars and a race track?
How about time with you reading books or colouring in (could you use a large tray to keep everything contained?)
Jigsaws ?

I lol'd a little at the idea of keeping a 3yr old quiet, sorry!

Den building?

Leon isn't very noisy but he is on the go! The only thing that keeps him engaged for long periods is the sand pit, reading or me drawing together. He also likes stickers.

Sometimes he has a bath just to play! We turn lights off and put candles on