i've got a few side projects on the back burner. if you're interested in learning something new, here are a few ideas:
1) create a better "subscriptions" page for youtube. they used to have "collections" where you can group together channels and see them separate from the main subscriptions. for our inconvenience, youtube dropped the feature. so you can build your own site where you implement collections however you want.
2) show a better netflix recommendations page. it currently includes movies you already watched, movies you downvoted, movies already in your queue. i think netflix dropped support for their APIs though, so might not be so easy.
3) in amazon's kindle books management, it only includes author/title. find a way to also include thumbnail / description and whether it has audio available.