One activity that Baby O loves is his bean bin. It was really easy and cheap to put together this toddler activity. All you need is a deep container of some sort. I used a gallon sized ice cream container with a good fitting lid. Then fill with beans. You can use one type of bean such as kidney beans, or you could mix it up and use assorted beans for variety. The great thing is that beans are pretty cheap so you could buy a few pounds for around $1 each and you'll easily be able to fill the bin up pretty well.
Once you have the bin filled you can pull it out occasionally for a switch up to play time. I'll set the bean bin in the floor of the kitchen along with a few cups and plastic bowls, measuring cups, ice cream scoops, etc. Then we sit down and he has fun sticking his hands in this cool sensory experience and scooping them out, then dumping them back in.
I do recommend supervision, especially with younger children. Little ones are notorious for stuffing beans in noses and ears. So you know your kid. If your toddler will shove things where they aren't supposed to go use your own judgement. And DO NOT LEAVE THEM UNSUPERVISED.