I felt the same when DS was doing 2 naps and it seemed all the activities in our area coincided with either the morning or the afternoon nap! I definitely preferred to let him have his nap(s) though and I just looked for other activities that did fit in to his nap routine at the time.
I think at this early stage in life -everything- is new to your baby, from music class to playing with a spoon and drum/pot. I dont really think they miss out too much when you dont take them to "classes". There's so much, even at home, for them to learn and experience and so much time to do it in! Whereas the process of such rapid growth, as babies experience in these first few years, is unavoidable and sleep is essential to that growth!
I think for me I started looking for activities because I wanted to get out of the house and do something! It was more for me than DS sometimes. The chance to get out and hang out with other mums is pretty important or we'd all go crazy!

But coming to that realisation helped me to accept to just let him have his nap and put his sleep needs first.
Our current activities are: One on one play: At friends houses with similar aged LO's (and similar nap times) Group play: Playgroup at a local church 9:30am-12 (although I usually only go for an hour or so. I'm not a member, you just show up for a gold coin donation) and for an "Outside Extra Animal Experience": A yearly pass for the zoo so we can go any time that suits us.
HTH!
