I think all my ideas are in that link above.
I wouldn't feel guilty over not setting up tons of messy play activities though, some of those on-line parenting blogs have great ideas but they can also go a long way to make you feel like a totally inadequate parent.
Talking about every day things, mentioning the properties of the items around you, is just as important if not more so. My DS was not really a fan of messy stuff that had been set up to play with it was a waste of time, but he was incredibly interested in exploring 'naturally occurring' items. So for instance:
- hard, soft textures, inviting LO to gently stroke or touch a flower petal and then compare to the hard rough brick flower bed it is planted in, that is sensory stimulation and doesn't need any setting up or clearing away. Same with a scrubbing brush and a soft sponge, just contrasts and high on the sensory in put.
- If I peeled an orange I invited him to smell the peel the moment I peeled it, to get the real zing of the scent. Opened herb jars and invited him to have a smell when I was cooking. Gave him bits of fruit peel and told him "don't eat this one" (and kept an eye on him) or melon or kiwi with skin left on and explained the different parts, again it's a contrast and using the tongue to enjoy the sensory contrast too.
And so on...just every day things, no extra work.