Hey hun... I have a few up my sleeve.....
Painting,
Colouring/drawing/scribbling ;)
Pasta play - raw on a tray makes fab noises.
- cooked is great to feel and squish
Spaghetti - cooked is also great to feel.
Jelly play, sand, water, water with bubbles.
Blowing bubbles.
Home made shakers - plastic bottles filled with marbles, rice, pasta, lentils, sugar... anything really all makes great noises.
Flour and water mixed makes a great short term cheap (and edible if they decide to have a chew) play dough - great for just manipulating and pulling
Cornflour play.
LOL just realised they are mainly food related, but it is all quick simple and cheap things to do that chances are you will already gave then in the house which makes it even easier :)
Singing - music channels/cds, having a little dance/ head bang plus you singing away will make your LO listen and take in the rhythm etc.
- nursery rhymes, with actions
HTH i'll have a think and see if I can think of some more