Drops is a language learning app similar to Duolingo, except it has many of the languages that Duolingo doesn't support, such as Thai. It mostly focuses on teaching you new words, with a catalogue of 2,000+ words divided into categories. It comes with exercises to help you improve your reading, listening, and writing skills. It's a bit light on grammar but is a good place to pick up some basic words and learn to make simple sentences.
Duolingo doesn't need to be introduced - it's just the biggest and most well-know free app for language learners. They have a comprehensive Mandarin Chinese course that teaches you vocabulary, grammar, tones, characters and pinyin. It's worth a try, especially for beginner learners.
This app is like Guitar Hero but for your piano. This is the perfect app for piano beginners, especially if sheet music intimidates you.
Learning a new language is hard, you need a lot of repeated exposure to the same words to make them stick. Here's the trick I use. I open ThaiPod101's live channel and let it run in the background while I do something else. For example, I can have it open while cooking dinner or tidying up. Even if I look at the screen only occasionally, I still get the benefits of being repeatedly exposed to Thai vocabulary. This works particularly well in combination with other learning methods. If you have a smart TV or a Chromecast, you can even play it on your TV instead of regular TV channels. The channel runs 24/7 and replays ThaiPod101 lessons.