In Denmark there is a period before the election day, where everybody are allowed to vote in certain places (the office of the municipal authority) in case the know they will not be able to vote on the election day. Prisoners are encouraged to make use of that opportunity in case they are on prison leave during this period.
If this is not an option, there is an opportunity to vote by post.
When inmates chose to vote by post, the voting is organized so that two staff members visit the prisoner in the cell and if the prisoner wants to give his vote the note is firstly placed in the envelope with the ID known by the election authority (to secure that one person does not vote twice) and then in an anonymous envelope that secures that the prison system cannot identify who is who.
There are occasional events and moments arranged for socialising. These are, however, rare. Television is free in all facilities. Most of the electoral debates, usually televised, are available to all prisoners