I remember feeling that my three month old (at that time) was bored with me. We were home alone all day. Once we started going out, she started seeing other people, other babies, other children, other stuff, she was very interested in all that. She hated the sling and loved the stroller. When she would get cranky/whiney I'd put her in the stroller and out we'd go. She calmed down and loved to watch what was passing by.
I also used www.pandora.com
and made sure we tried all sorts of music types from classical to reggae.
Library time - I thought it would be a waste, but it's actually social hour for babies under two. She loves it. We started this at nine months.
Things for baby to puzzle out. My dd loves to pull things out of the diaper bag, or try to figure out how to pull things out of bottom stove drawer or pull things out from under the table... So I make it a game for her. I put different things in the spare diaper bag and let her pull them out and look at them. Other times I make it a bit more challenging for her to figure out how to get things out... zipper a bit more closed.
She is just starting to like to look at books at 10 1/2 months. All previous attempts at reading to her were frustrating as she only wanted to chew on the books and was upset when she was only able to look at them.
I am looking forward to baby swimming time.
And then when we're back home I think of her toys that she's just bored with what she has. I wish there were a toy exchange where toys were automatically sanitized too! It's not the quantity of toys, but the exploration of something new.
oh, and physical time. We spend time rolling over, back & forth, helping her crawl by moving her legs, stretches, hanging upside down by feet - she loves this.
We hope she will enjoy the baby backpack for hikes. Keeping fingers crossed. The only time she tried she was good 1/2 the hike and the other 1/2 we were carrying her in our arms - the backpack was no longer an option as she strenuously, vocally objected.