A discussion with a friend yesterday about portable audio recorders had me thinking about something fun to do while travelling that I only really recently realised I should try doing more of.
That is: Recording short audio clips (in addition to any video clips I'm already capturing, though again... more random clips from different places are again something fun to have) from various places during my travels - and in particular, doing it for any public transit route you end up spending a lot of your time during the trip using.