Lately I've been lining up things for Bear to grab and touch and explore. I sit him on my lap at the table or lay him next to a bunch of different colorful things around the house. Colored plastic baby spoons (2.99 for 10 at the grocery store) A bright blue plastic measuring cup, a plush toy (usually his "binky bear" its a Wubba-nub) and I let him hold them and pick which ones he wants. The way I see it if I give him a some shiney monster toy off the shelf he'll have no idea what it is (because I have no idea what it is) but if it's an every day thing he's more likely to recognize it later on.
Also we have so much fun with paper towel rolls the other day, I would talk into it and he thought it was hilarious.
Make sure everything you give them in OK to put in their mouth and CLEAN! A great way to clean toys is 1 cup white vinegar and 1 cup water and after washing them just dunk them and let dry. Non-Toxic and once vinegar is dry it has no smell!