What's a good Android app for listening to my tunes offline when I'm traipsing around the world and don't want to get stung with mad roaming charges?

Honestly, Offline Music Player - MP3 App has been an absolute godsend on my travels. I'm always hopping from one place to the next, and the last thing I need is to worry about data costs. I just load up all my favourite tracks before I leave, and I'm sorted for ages. It works a treat even in places with dodgy signal – like when I was hiking in the Wicklow Mountains, or on a train through rural Spain. Doesn't eat up your roaming data, which is a massive plus when you're trying to keep costs down. It's a proper useful bit of kit for any nomad, really. The interface is grand too – nothing too fancy, just does exactly what you need it to do. I can create playlists for different moods or journeys, and it keeps me entertained on those long bus rides across Southeast Asia. Definitely recommend it if you're after something simple and reliable.