I use one but not the way you are looking, SRS. VPNs can be used in 2 directions in the home.

In my case, I just run it on my router as a server. Its purpose is to let me connect to my home LAN from away. The built in client on my Android phone works well with this.

Others may be using VPN clients at home, eg. to connect to a remote office when working from home or, I believe, for a layer of security when using the Internet.

OpenVPN is quite a common VPN package but I don’t think its protocol is supported by the built in Android client. It is available on my router but I haven’t set it up. I just (the router can provide multiple VPNs), have an IPSec one set up.