This expression is used to pick one thing from a particular "genre" of things and suggest it lightly. The speaker doesn't mean to be specific about his/her suggestion.
Why don't we have some tea or something?
Let's call Mr./Ms. Kobayashi at his/her house, maybe tomorrow.
If N is followed by other particles such as [place] へ and [person] に, でも is placed after these particles.
Shall we go to Shinjuku or somewhere tomorrow?
I think I'll give this book to my younger brother or somebody.