The online Image Gallery and Special Collections of Dublin's City Libraries continue to grow at a pace and are definitely worth losing yourself in for a few hours.
In the last couple of months some 530 photos have been uploaded to the image bank in collections called Vanishing Dublin, Dublin Pubs, and Working for the City. The latter, the most recent collection, features photos of City staff at work (mainly) in the 1950s and '60s. Heart racing stuff for Health & Safety professionals!
The Special Collections portfolio is also great fun to rummage through. My favourites include the tram timetables, old maps (I confess to being a map-nerd) and a 1736 newspaper advert for a tincture that 'immediately expels wind from the stomach' and sorts out your belchings and hyck-ups. Useful stuff!