What do you do all day with your 18mo?

[BettySwollux]

DS2 is 18mo, and I feel stuck in a rut for inspiration how to entertain him.
Our daily routine is;
Up at 7ish, breakfast and dressed,
Snack at 10ish,
Nap at 11.30
Up at 1, lunch.
Bath 6.30, milk, watch ITNG and bed.
Play is mainly reading his books, over and over and over, or building blocks or playing cars.
Tue, wed and thur mornings we go to toddler group.
We go for a walk in the afternoon.
He isnt interested in anything arty, tries to eat pencils and chalk. His only tv indulgence is ITNG before bed (he likes the ending when the characters go to sleep)but Im not keen on him watching too much, its not like its never on, as DS1 is 11, so we have simpsons etc.
He just seems a bit bored sometimes, and while his attention span isnt great (whose is at that age ), I would like some ideas to occupy him, so, can you tell me what you get up to all day please?

I take DD (21 months) to the park, playground and library lots.

She likes her CDs (especially one with children's songs on and an In the night garden one) and dancing and singing to them.

She loves dressing up (she has a few cheapo dressing up costumes and some of my old jewerelly and hand bags).

We have a sandpit and small trampoline in our tiny back yard, she plays out there on dry days.

She likes play-doh a lot. She ate it at first though.

Sometimes I let her play in the bath for a change on rainy days, often I get in with her too

16mo dd here -

Playdough, keep meaning to do some painting too.
Fill a shallow tray with water, put some bowls/dishes/spoons etc in, let her play with it (better in warm weather)
Swimming?
We do the park and library a lot as well as playgroup and music group.
Walking to park - only 5 mins away but can take about half an hour while she stops to investigate everything.
Just going in to different rooms in the house, climbing on the spare room bed, investigating the soaps etc in bathroom.
BLowing bubbles.
Dancing to CDs
Playing in the garden.
Rotating toys so they're not all out at once - so I can get stuff out she hasn't seen for a while.
Baking (can get messy but fine for us as the dog eats up any mess on the floor).

We have a toy library near us so get new toys out of there every week (not sure if they have them in UK? I live abroad).

They do have a really short attention span at this age. I used to work in childcare with 20 under-2's and we would just keep changing the activitiy every 20 mins or so.

WSS, I totally forgot about the local toy library, will give that a go, thanks.
We have tried play-doh, but he just eats it lol.
DS1 has a massive trampoline in the garden, but I cant get on with him as had SPD in preg and still painful, so ok when DS1 home, but darent let DS2 on by himself.
We go to the park now and then, but he wants to get in the river with the swans, so that puts me off, but he does like playing with the balls in the garden.
Thanks for all suggestions - keep 'em coming!