Q: Is it haram (forbidden) to play cards socially without any gambling involved?

A:
If there is gambling involved then it is Haraam. If there is no gambling involved then it is detestable as it is generally frivolous and time consuming. However, if it leads one to being negligent of Salah and other obligations like obeying one's parents etc or makes when negligent of other responsibilities or if it is associated with any other impermissible activity found then too it must be avoided.

A Muslim must value every moment he is blessed with and use it that would benefit him in some way in terms of this world or the hereafter and avoid every type of futility.